Minnesota Local History Blog.

Minnesota Local History Blog.

Advice and help with building history capacity.

The Minnesota Historical Society’s Local History Services helps Minnesotans preserve and share their history. This blog is a resource of best practices on the wide variety of museum, preservation, conservation, funding, and non-profit management topics. We’re here to help.

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Seasonal Window Considerations and Treatments

Windows have of course long been called the eyes of buildings as they are usually a leading character-defining feature that transmit light but also illuminate an important component of the Industrial Revolution and construction. They tell us a lot about their host buildings, such as their owners and their tastes and interests, as well as styles, uses, and alterations over the years.

Comstock House exterior window.

Comstock Historic House, Moorhead, Minnesota.  Source: MNHS.

This Minnesota Historical Society (MNHS) museum property was constructed in 1883 for a prominent Red River Valley family who was active in railroad and educational pursuits. Storm windows paired with regular sash windows help provide thermal protection from the prairie elements.

The multibillion dollar window replacement industry is able to dedicate considerable funding to try to convince people that only replacement windows will eliminate drafts. However, here in a state with weather as diverse and dynamic as Minnesota’s, people have long thought of ways to make their buildings as weathertight as possible. These options allow people to continue to enjoy the effects of the painted wood frames and the unique types of window glazing like crown, cylinder, and faceted glass that would otherwise likely end up in a landfill.

“Unlike historic windows, new window assemblies cannot be repaired; they can only be replaced once again. The sustainable choice is to repair historic windows whenever possible.” National Park Service 

Of course, the main requirements that window structural integrity rests on are regular observation and maintenance. Repairs should be made as soon as possible. Finding professionals who are experienced at window repair and rehabilitation is very important. National Park Service’s Preservation Brief 9 and 13 along with Preservation Tech Notes Windows 1-22 are excellent starting resources when considering window care and weatherization. More effective than having weathertight windows is ensuring that, especially, ceilings and attics are insulated and, less so, exterior walls are insulated too. 

Storm Windows 

“A 2002 study confirmed that installing a storm window over a historic window can achieve a similar thermal performance to that of a new low-E vinyl replacement window. This experiment conducted by Lawrence Berkeley National Laboratory also noted that remaining air infiltration around the historic window and storm assembly is a matter of occupant comfort rather than energy efficiency.” Weatherization: Windows and Doors National Park Service 

The use of storm windows, which have supposedly been around since the eighteenth century, can be effective year round, while only changing to screen windows the locations that need to be opened for ventilation during the summers. Thankfully, there are exterior and interior storm windows that come in a variety of materials, colors, and finishes that can complement historic buildings. Storm windows should match the overall style and color of the main windows they are serving. Speaking with a historic architect or building preservation professional can be of considerable assistance when navigating the many options to find suitable ones for the subject building. 

Sometimes, some of the storm window suppliers are from more obscure manufacturers. Often finding the most in-kind type of storm window may require contacting the manufacturer who will hopefully find the best match through a deep array of options. Existing storm windows should be retained, either on the building or in storage, as often as possible. Many of the finest historic storm windows even included true glass dividers of wood and stained glass margin lights. 

Storm windows significantly reduce the amount of sound that is transmitted through an opening. A single-pane historic window with a storm window provides greater noise reduction than a double-pane replacement window because there are two different systems instead of one; having two different systems provides a noise break. Some storm windows also integrate or have a basic surface for applying a UV-protection film or privacy glass, film, or safety glass.

Blue Goose Cottage exterior near a lake with two people on the front stoop and a screened rear porch.

Blue Goose Cottage, Idlewilde, Lake Osakis, Osakis.  Source:  MNHS.

This 1940 photograph of this resort cottage shows how screen windows and screen doors were utilized in the summer months to repel insects while allowing cross ventilation.


Most commonly wood or metal, these devices, when closed shut over windows, can help weatherize the openings in a considerable way. However, they should not be utilized unless they were featured on the building historically. Adding features that were never there on the building creates a false sense of history. However, when there is photographic or physical evidence they had been utilized, there are regional manufacturers, repairers, and restorers of this feature, including here in Minnesota. 


Usually more useful in summer than in winter, these exterior window coverings are usually made of some type of cloth but also can be made of metal or other materials. They often keep out the sun in the summer but also can find a way to reduce wind and rain in the spring and fall. In commercial buildings, they would help keep interiors and window shoppers more comfortable and reduce HVAC costs. 

Boy standing with a bike in front of a building with scalloped awning.

T.F. Cann Window Shades and Awnings, Seventh and Hennepin, Minneapolis. Source: MNHS.

This 1899 photograph shows an interesting scalloped awning on the porch of this building.

Treatments / Accessories 

Using drapes, curtains, and sheers, as appropriate, to minimize drafts and temperature fluctuations while providing privacy, defining views, and creating the right ambience has long been considered an economic option for reducing temperature changes, solar fading, and sound transmission within a building. 


Drapes are usually of very heavy fabric that is tightly woven and effective at greatly reducing drafts and separating heat and cold.

Governor's Reception room with large desk and chairs in the foreground with three windows covered with decorative pelmets and drapes in the background.

Governor’s Reception Room at the Minnesota State Capitol, St. Paul, Minnesota. Source: MNHS.

The decorative drapery and pelmets (located at the tops of the window openings) provide for dramatic and decorative shading of light and weatherproofing in this landmark, which was constructed from 1896 to 1905.


Curtains are slightly more lightweight than drapes and can be effective for filtering light and sound and helping to provide a lesser amount of weatherproofing. Made of a variety of fabrics and fibers that have transitioned from natural to synthetic over the years, curtains also help provide decoration and privacy.

Four women sit at a table working with sewing lightweight fabric.

Handicraft workers making curtains for Gillette Hospital, St. Paul.  1936.  Source: MNHS.


This thin gauzy material is more minimally effective at weatherization but is often considered beautiful in window treatments while providing some privacy. It is utilized together with curtains or drapes and is sometimes used all by itself. Historically, materials such as cotton and linen were used while in recent years polyester and nylon have been featured.

A decorative Victorian parlor features various pieces of furniture and two sash windows.

Historic Forestville, Minnesota.  Source: MNHS.

The sheer curtains and blinds provide a layered appearance that gives versatility to regulating temperature, light, and privacy in this decorative nineteenth-century space.


Blinds have been utilized for centuries to enhance solar and heat gain in the winter and minimize solar and heat gain in the summer, with more natural materials like linen and wood being replaced with plastics in recent years. Horizontal blinds are usually designed more to control light and heat gain while vertical blinds are utilized for privacy unless they are closed. 

Roller blinds come in a variety of colors, privacy levels, and patterns. Some of the blinds are available with an open weave and some with UV protection built into the material. Historically, material such as linen and cotton was utilized. Some of the more modern roller blinds material includes polyester and vinyl. Some of the material used to make blinds is thicker and occasionally quilted to provide additional solar and thermal protection.

Related National Park Service Preservation Briefs and Tech Notes

Preservation Brief 3, “Improving Energy Efficiency in Historic Buildings”
Preservation Brief 9, “The Repair of Historic Wooden Windows”
Preservation Brief 13, “The Repair and Thermal Upgrading of Historic Steel Windows”
Preservation Brief 44, “The Use of Awnings on Historic Buildings: Repair, Replacement and New Design” 
Preservation Tech Notes Windows 1-22

Creating a Disaster Response Kit

By: Megan Narvey | Conservation | December 21, 2021

Imagine that overnight, a pipe bursts in your collections storage room. You get to work in the morning, and one of your shelving units is soaked. You make sure everyone is safe, turn off the water, and activate the call tree described in your collections emergency plan. Thankfully, your emergency plan has detailed instructions on how to salvage and dry out the wet collection items! But first, you’re going to need to find some polyethylene sheeting, towels, blotting paper, a spare table, a clipboard, a pencil, nitrile gloves, a mop, a fan, and a flashlight. How quickly are you going to be able to gather your supplies?

Response speed is essential when salvaging collections materials in a water-based emergency situation. Very few types of materials in museum collections are immune to water damage. The longer something is wet, the worse the staining or bleeding dyes will be, and the more likely things will become warped, corroded, or moldy. Personal safety must always come before collections are salvaged, but once the situation is safe you will want to act promptly.

The first step to take to reduce the impact an emergency will have on the collection is to develop a collections emergency plan. After you have your emergency plan, the next step is to create a disaster response kit.

What is a disaster response kit?

A  disaster response kit is a collection of tools, equipment, and other materials that can be used to respond to a collections emergency. The kit should include enough supplies to fully respond to a small emergency, or to adequately respond to a larger emergency until more supplies can be purchased. It may be stored in a fixed location, such as a supply closet, or it may be mobile so that supplies can easily be moved to the needed location. The kit might be a small one for use in a single storage space; a larger one for your entire organization; or an even larger one to be shared between multiple organizations in a region.  

The contents of the kit should be specific to the needs of your organization. If you live in a flood prone area, you may want to focus efforts on preparing for that situation. Similarly, if your collection consists mostly of books and paper items, then your kit should be aimed at the needs of these materials. 

What does a disaster response kit contain?

Your disaster plan should help you prepare the contents of your kit by answering the following questions:

  • Which emergency situations are the most likely to occur? 
  • Which emergency situations would have the biggest impact on my collection? 
  • What materials in the collection are most at risk in an emergency situation?
  • What techniques and materials would be needed to recover the affected collections?

In general, a disaster kit should contain the following key components: a container, documentation materials, instructional documents, personal safety equipment, tools for scene/environmental control, collections salvage supplies, and other tools. Here are some examples of what you could include in your kit.


  • Backpacks
  • Wheeled crates
  • Plastic storage bins
  • Milk crates
  • Mobile trash can
  • Cabinets with doors/wheels
  • Push carts

Documentation Materials

  • Name tags
  • Clipboard
  • Notepads
  • Mechanical pencils, Sharpies, grease pencil, pens
  • Tape measure
  • Tie-on labels (paper or Tyvek)
  • Adhesive labels
  • Disposable camera

Instructional Documents

  • Emergency Salvage Wheel or other salvage guidelines
  • Copy of disaster plan
  • Floor plans
  • Gallery case access guides
  • Priority object locations
  • Loan agreements
  • Object damage reports

Other Tools

  • Wrench
  • Screwdrivers
  • Hatchet
  • Utility knife and blades
  • Nylon or polypropylene rope
  • Cable ties
  • Scissors
  • Crow bar
  • Flashlight with batteries
  • Waterproof extension cord/power strip
  • Wet vac
  • Fans
  • Dehumidifier
  • Portable generator
  • Folding tables

Personal Safety Equipment

  • Safety goggles
  • Disposable apron
  • Hard hat
  • Hand sanitizer
  • Disinfectant wipes
  • Reusable respirators or N95 masks
  • First aid kit
  • Nitrile gloves
  • Work gloves
  • Drinking water

Scene/Environmental Control

  • Temperature and relative humidity spot checker
  • 6-mil polyethylene sheeting
  • Garbage bags
  • Duct tape
  • Caution tape
  • Mop and bucket
  • Door wedges
  • Fire extinguisher
  • Walkie talkies
  • Head lamp with batteries
  • Work lights and extra bulbs

Collections Salvage Supplies

  • Polyethylene zip top bags
  • Cotton string
  • Nylon monofilament
  • Plastic wash tubs and trays
  • Paper towels
  • White cotton rags
  • Unprinted newspaper
  • White cotton terry cloth
  • Wax paper
  • Freezer paper
  • Reemay
  • Mylar
  • Corrugated plastic board
  • Screens
  • Clothes pins/plastic clips
  • Clean brushes
  • Wood blocks or similar for stacking and propping things off the ground

More considerations

  • Disaster response kits require upkeep and maintenance. 
  • Some components of the kit will expire (nitrile gloves, first aid kits, batteries, etc.) 
  • Kits should be regularly inventoried to ensure that all the tools and materials you expect will be there when needed.
  • Many (not all) of the materials are consumables and will need to be replaced after use.
  • Ensure that your organization has a strategy to keep your kit sustainable over the long term. 
  • The creation of a disaster response kit can be funded with a Minnesota History and Cultural Heritage Grant! Read more about these grants at this link, and by watching the video below.   

More resources

MNHS Grants Manual - see page 71 for specific details about creating a disaster response kit.

Connecting to Collections Care webinar: Collections Emergency Kits

Conservation Center for Art & Historic Artifacts: Emergency Supply Kits

Conserve O Gram: Emergency Cart for Salvaging Water Damaged Objects

MNHS: Disaster Response and Recovery Resources

Radioactive Collections

By: Megan Narvey | Conservation | April 12, 2021

I recently had an interesting question sent to my inbox about the safety of uranium-containing glass in a museum collection.

“So, I read The Radium Girls and had watched that webinar on hazards in museum collections. Yep, I put two and two together and bought a black light flashlight. Snapped these pictures and wondered, is it safe to keep them on display or any precautions?”


Black light photograph showing glassware in a museum case glowing bright green.

Uranium glass fluoresces bright green under ultraviolet light. Photo courtesy of Lindsay Marshall, Lake of the Woods Historical Society.

Here was my response:

Great question, and love the black light photos! (As an extra safety precaution on top of everything else, I recommend wearing UV-protecting eyewear when using a blacklight – polycarbonate safety glasses are one good option). These objects are really cool and I bet people would love to learn more about them.

The only real way to know how much precaution to take with any radioactive artifact is to measure the radiation coming off it using a Geiger counter. You might be able to partner with local health & safety officials to test the radioactivity of the glass. I don’t know if you’ve used a Geiger counter before, but it’s totally non-invasive, non-destructive testing. 

Radiation is considered in “doses”, as in – how much radiation per year can I safely be exposed to? You can take one 'big' dose of radiation once per year and be safe, or you can get small exposures to radiation more frequently, and be at the same risk level. The risk is much less for a visitor who comes in occasionally and doesn’t spend all that much time near the radioactive glass compared to a collections worker who is working directly with these objects every day.

One way to mitigate risk is to limit the amount of time you spend with a radioactive object. Other ways to mitigate risk are to increase distance and barriers between you and the objects – good practice would be to always handle this glassware while wearing nitrile gloves; and to display it behind glass in a display case rather than on open display.

The good news is that the amount of uranium in glassware (or Fiestaware) is quite low – often as low as 0.5% of the weight of the object. They don’t emit much radiation. So it’s safe to have these kinds of objects in museum collections, although I recommend taking precautions like those I mentioned above. 


For those who want to do more research, these are all great resources: 

Managing Small Radioactive Collections in the UK: Experiences from the Polar Museum, Cambridge

Uranium Glass in Museum Collections

Uranium in a Cupboard Near You!

Seeing More: glow-in-the-dark glass

EPA: Radioactivity in Antiques

Radium Girls: The dark times of luminous watches

MN Department of Health: Radiation Control


Sustainable Museum Lighting

By: Megan Narvey | Conservation | March 2, 2021

Museums becoming more climate-friendly is increasingly important in the field, because the effects of climate change pose a huge threat to collections. It may seem counterintuitive to pair collections care with environmentalism, but when it comes to museum lighting they really go hand in hand. Almost every action you take to reduce energy consumption from lighting will also help you to preserve the light-sensitive items in your collection. On top of that, any action you take that results in lower electricity bills means more money you can spend on other aspects of collections care, like archival boxes and padded hangers!

I recently attended an interesting webinar about environmental sustainability and museum lighting presented by David Saunders and hosted by the Icon Environmental Sustainability Network. He said that although the biggest energy consumer in most museums is the HVAC system, museum lighting represents a sizable chunk of electricity use. In his talk, David Saunders broke down sustainable museum lighting into five actions. 

  1. Switch to LEDs
  2. Increased use of daylight
  3. Reduce light levels
  4. Shorter display times
  5. Better time management

From left to right: incandescent, fluorescent, and LED light bulbs. Photo by Megan Narvey.

Switch to LEDs

Switching to LEDs has an immediate impact on electricity consumption because they are by far the most energy efficient type of light bulb; in large part because they are so efficient at converting electricity into light rather than heat (cough cough incandescents). Because LEDs have a longer life than incandescent and fluorescent bulbs, there is also a reduction in the use of raw materials. 

LED lights emit little to no UV light, which is a huge benefit for the preservation of light-sensitive collections. So LEDs are a great lighting choice for many reasons: energy efficiency, lower long-term financial burden, less maintenance, and they’re better for collections. 

Increased use of daylight

This option might surprise many museum professionals! The argument here is that daylight is a free energy source, so it is completely environmentally friendly. The problem is that it’s difficult to control. The brightness, color, and direction of daylight varies depending on the time of day, the time of year, and clouds! 

Direct sunlight will quickly damage light sensitive objects, even with UV filtration. Therefore, you need control systems like shades, blinds, curtains or baffles; and you might need to change their position throughout the day. A really cool solution to this problem is the use of electrochromic glass (also known as “smart glass”), which darkens or clears automatically depending on the amount of sunlight hitting it. 

Reduce light levels

It’s important to limit the amount of light in museum display areas because light can damage many types of collection items. Lower light levels also benefit the environment! But there is only so much you can do to lower light levels before your collection becomes inaccessible because you can’t see it. It’s possible to create a space with very low light levels that is still functional - for example by featuring individual objects with spotlights. 

The use of dimmer switches is a simple way to increase your control over light levels. The sweet spot between preservation and visibility is 50 lux for highly light sensitive materials, and 200 lux for moderately light sensitive materials. Lux is a unit for measuring the amount of light in a square meter, and can be quantified using a light meter like this

Shorter display times

One way to achieve shorter display times that will benefit both the collection and the environment, without resulting in reduced access, is to use manual, timed or automated lights that respond to visitors. You can install proximity sensors that turn on the lights in an area when they sense movement, ensuring that the lights are off when nobody is in the room. Shorter display times can also be accomplished with an object case where the visitor presses a button to activate lights to view the contents for a set period of time.

Better time management

The final option can best be summed up by the old joke about dads running around the house turning off all the lights in unoccupied rooms. Ensuring that you turn the lights off in storage when you’re not working there, and turning the lights off when the museum is closed, can have a big impact. 

If you’re interested in learning more about environmental sustainability in museums, check out these organizations: 
Museums and Climate Change Network
AAM - Environmental Sustainability
Sustainable Museums
Sustainability in Conservation
Coalition of Museums for Climate Justice

Learn more about light as an agent of deterioration at the Canadian Conservation Institute.

To see more of David Saunders' work on museum lighting: 
Podcast: David Saunders on Museum Conservation and Lighting
Book: Museum Lighting - A Guide for Conservators and Curators

Fun Facts About Museum Pests: Silverfish

By: Megan Narvey | Conservation | January 20, 2021

The bane of archives, libraries, and paper-based collections everywhere: the silverfish!

In previous installations of Fun Facts About Museum Pests, I discussed carpet beetles and clothes moths, two common museum pests with similar life cycles (their larval forms cause the most damage to collections) and food preferences (proteins). Silverfish are completely different: they don’t have a larval stage. Instead, their young predecessors are called “nymphs” and they just look like smaller, translucent versions of adult silverfish. And rather than proteins, they like to munch on starches.


Silverfish are a wingless insect that can be up to 10-15 mm in length. Their bodies are easily recognizable as they are “carrot-shaped” and covered in silver or gray scales, with long antennae and three long tail-like bristles.

Detailed photo of an adult gray silverfish on a neutral background.

Adult gray silverfish (Ctenolepisma longicaudata); Pest and Diseases Image Library,

Damage to cardboard by small blue silverfish (Lepisma saccharina); Clemson University - USDA Cooperative Extension Slide Series,


Silverfish are omnivorous and will eat both cellulose and protein materials. They are especially fond of the sizing of paper, and the glue and paste in book bindings. They are known to enjoy eating wallpaper, and the glue holding it to the wall. They will eat any material that has been treated with starch, gelatin, or organic dyes, including textiles like silk and cotton. They also eat microscopic mold on the surface of items. 

Silverfish have weak mandibles and feed on materials by scraping at the surface. This causes damage that appears as irregular thin patches on the surface, occasionally breaking all the way through to leave oddly-shaped holes with ragged edges. They will sometimes eat away preferentially at organic dyes, leaving an interesting trail of damage on labels, prints, or wallpaper, with some colors eaten first. 

Silverfish thrive in cool, damp, dark environments. Finding silverfish is a strong indicator that you have moisture problems - they’re most likely to be found in attics, basements, bathrooms, and kitchens. Where there are silverfish, often there is also mold. 

You’re unlikely to see silverfish scampering across the floor. They prefer to lurk in cracks and crevices and behind walls. They’re nocturnal, and hide during the day or when the lights are on. If you come across silverfish at random in daylight, it means you could have a big infestation somewhere in your building.

Silverfish live as long as three years and will molt up to 50 times. They can live for nearly a year without feeding! Eggs will hatch after about a month, and the young spend about 3 months as nymphs before becoming adults. They multiply quickly!


Use sticky traps to monitor for a silverfish infestation. They can help you locate where the pests are entering an area, and help you keep track of the success of your preventative measures. You can also identify an infestation by looking for small dark frass, yellow stains, scales and the telltale signs of damage on paper. 

Because silverfish like the damp, the best way to rid yourself of a silverfish problem is to dry out your environment. If you can’t eliminate moisture, move your collections into a drier space to protect them. Keeping the room at a temperature below 60 degrees will also help slow silverfish down.

You can make it more difficult for silverfish to access collections items by keeping everything up off the floor on shelving, and by controlling food sources by removing cardboard boxes and paper products that are not part of the collection.

Use freezing treatment to kill silverfish and their eggs on artifacts. It can be difficult to completely eliminate a silverfish infestation. If monitoring indicates that you still have an issue despite taking preventative measures in your environment, you should work with a conservator and a pest management expert. Never put pesticides directly on your collection. 

Silverfish in his Christmas best. Art by James Hales, photo by Megan Narvey. 

I’ve been somewhat fond of silverfish ever since one of my grad school professors drew a picture of one in its “Christmas best” during a lesson. It's just so dapper!

Fun Facts About Museum Pests - Part 2

By: Megan Narvey | Conservation | November 3, 2020

In Part 1 of this series, we talked about the common clothes moth. Today, I'd like to tell you about my favorite museum pest. When I say favorite, I definitely don't mean that this is the best kind of pest to find in your home or your collection. They're not easy to detect, can be very difficult to eradicate, cause a lot of damage, and can live basically anywhere! However, when they’re not ruining your wool rug, they have been put to good use in some professions. And the larvae have the best nickname of any museum pest. Today, let's learn more about the carpet beetle!

Multiple life stages of a carpet beetle.
Clemson University - USDA Cooperative Extension Slide Series,
  • Carpet beetles are a type of dermestid, also sometimes referred to as “skin beetle”.
  • Some types of dermestids are really helpful. Forensic entomologists use them to learn more about criminal investigations, and taxidermists and natural history museums use them to clean animal skeletons.
  • A carpet beetle is the same shape as a ladybug, but much smaller - only a few millimeters long! They are usually black or a mottled yellow, black, and white.
  • Adult carpet beetles feed on pollen, so it's easy to accidentally introduce them to your home or museum by bringing in fresh cut flowers. They can also fly, and enter through open windows.
  • Another common source of infestation is having bird or wasp nests on your building.
  • Even though adult carpet beetles prefer to live outside, they like to lay their eggs inside. Female carpet beetles can lay about 50 eggs.
  • The larval form are called “woolly bears” because of their densely packed hairs.
  • The late stages of woolly bear growth can be up to twice as big as the adult beetle!
  • Just like with clothes moths, these cute little fuzzy larvae are the ones responsible for damage to the collection.
  • Woolly bears feed on wool, fur, felt, silk, feathers, skins, and leather, and they’re more likely to be found in dark, undisturbed areas. However some will also eat things like seeds and grains; and they will eat through other materials if a food source they want is nearby.
  • Some woolly bears can live for up to two years if the conditions aren't ideal for them to grow and pupate!
  • As woolly bears grow, they shed their skins. These shed skins are one way to identify that you have a carpet beetle infestation.
  • Another good way to identify a carpet beetle infestation is on your window sills. Adult carpet beetles are attracted to light, and often congregate near windows.

The best way to prevent a carpet beetle infestation is through housekeeping and integrated pest management. If you spot a carpet beetle or woolly bear on your collection, it's usually a good idea to bag that item right away. Many museum objects are safe to freeze if following the proper protocols, and this can kill carpet beetles, woolly bears, and eggs. Always consult a conservator if you're not sure whether a treatment method will be safe for your collection.

More Resources
Bell Museum: Meet the Beetles
Entomology: Carpet Beetles
Black Carpet Beetle
Varied Carpet Beetle
Solutions - Low Temperature Treatment

Fun Facts About Museum Pests - Part 1

By: Megan Narvey | Conservation | October 20, 2020

Not many people go into museum work because they love insects, but pest management is one of the most important tasks you can do to protect your collection. Common museum pests can wreak havoc before you know it, and they affect everyone - from your wool sweater collection at home to the pristine store rooms of a national museum. Today let’s learn some fun facts about the common clothes moth.

Webbing clothes moth: larva, pupa and adult on wool.
Clemson University - USDA Cooperative Extension Slide Series,
  • Clothes moths come in two major types: the casemaking clothes moth and the webbing clothes moth. They look similar but the webbing moth larvae creates patches of silken webbing to protect itself while it munches on your collection, while the casemaking moth creates a small tubular case.
  • Clothes moths are only about half an inch long.
  • Adults will lay about 40-50 eggs, which are too small to easily spot on an object. The larvae look like little white caterpillars.
  • Only the larvae will cause damage to your collection, but it’s easier to spot and trap the adults. You can buy clothes moth pheromone traps to easily monitor for them.
  • These pests feed exclusively on animal-based materials like wool, fur, silk, feathers, taxidermy, and leather.
  • Some warning signs to look for include webbing or silken cases on objects, and shedding fur as the larvae eat along where it connects to the skin.
  • Moths also leave behind a fecal material called frass, which looks a lot like sand. Moth frass is the same color as the material they are eating, so it can sometimes be quite colorful.
  • Moth larvae don’t like light, so you can often find evidence of their presence in folds, cuffs, and crevices on objects.

The first step to protecting your collection from museum pests is learning how to identify them and spot damage before it gets out of control.

More Resources

Casemaking Clothes Moth
Webbing Clothes Moth
Entomology: Clothes Moths
Identifying Museum Insect Pest Damage
Museum Pests e-learning tool
Insect Pests in Museums Identification Poster

Tips for Caring for Street Art

By: Megan Narvey | Conservation | June 15, 2020

What is street art?

Street art is a cultural and artistic expression that has been created or installed in a public space. When there is prior permission and planning, it is often referred to as public art. Sometimes street art is considered vandalism, but other times it is embraced and valued by the neighborhood.

Street art can take a number of forms, including paintings, sculpture, posters, or even yarnbombing. Murals are paintings that have been created on walls and other architectural spaces, and are not portable. Street art paintings can also be applied on fabric or plywood boards.

Three images showing different types of street art in St. Paul, Minnesota.
Different kinds of street art seen in St. Paul, Minnesota.

Why is street art difficult to preserve?

Street art is usually not intended to last forever. A mural that is created after careful planning, using the most stable materials, and receiving regular maintenance, might have a lifespan of 20-30 years. Conservation and maintenance over time costs money, and it’s very rare for there to be long-term financial support for street art. Additionally, it’s often unclear whose responsibility it is to care for street art. Typically, the intellectual property belongs to the artist while the physical work might be owned by the building owner where the artwork was installed. Ideally, the decision to preserve street art should be agreed upon by the artist, building owner, and neighborhood. 

Here are the most typical problems with preserving street art: 

  • Materials used in its creation were not designed or tested for longevity
  • Misguided attempts to preserve might cause more damage
  • Vandalism
  • Exposure to weather, light, and pollution
  • No funding for maintenance or conservation treatment
  • Artist is unknown
  • Removing street art to preserve in more ideal conditions, such as in a gallery or museum, can strip the artwork of its context and identity, preserving the material but not the meaning 

Recommendations for preserving existing street art

Document the mural with high resolution photographs. Try to record the artist’s identity and the types of paints and other materials used. Add this documentation to a local street art register if possible (examples: George Floyd & Anti-Racist Street Art, Chicago Mural Registry). 

Regularly assess the condition of the street art using a condition report form such as this version provided by the Canadian Conservation Institute: Outdoor Mural Condition Report Form. Conducting an annual inspection will allow possible issues to be addressed before they cause irreparable damage.

Encourage artists to become familiar with best practices for creating street art in order to choose materials and locations that will naturally enhance preservation - for example, avoiding south-facing walls where light damage and heat damage from the sun will be more intense, and choosing paints with light-resistant pigments. 

Coatings can be applied to protect the paint layer and to make it easier to remove graffiti. Coatings should be durable, permeable, reversible, and compatible with the artwork, so that they can be removed later without damaging the paint layer. Always test a coating in a small area before applying overall. Depending on a number of conditions, a clear coating can become cloudy, yellow, or begin to chip and flake. Don’t apply impermeable and irreversible coatings (such as polyurethane), as these will cause more damage over time. Find more advice on coatings here

Don’t attempt to preserve the artwork by covering it with glass or Plexiglass. This will trap moisture and dirt and speed up deterioration. It will also alter the appearance of the artwork, and make it more difficult to see. 

Use overhangs and gutters to redirect water away from the artwork. 

Maintain street art by sweeping around it, cutting back nearby plant growth, keeping gutters clean, and promptly removing graffiti or vandalism. You can install signage nearby with contact information for reporting graffiti or vandalism. 

If the mural is washed, it should be done as gently as possible without detergents and with minimal water pressure. Test a small area before cleaning overall. 

Try to obtain the permission of the artist, building owner, and neighborhood before moving street art to a protected location for preservation purposes. Document the original location and context as much as possible beforehand, and keep these records associated with the artwork. 

Further Reading

Best Practices for Creating Street Art

“Conservation guidelines for outdoor murals”. Canadian Conservation Institute. (2017)

“Mural Creation Best Practices”. Rescue Public Murals. (n.d.)

Williams, B. “Techniques of Community Murals” Community Public Art Guide. (n.d.)


Di Giacomo, G. “Top Tips in Street Art Conservation”. Street Art Today. (2018)

Garcia, R. “Ephemerality, Values and New Models: an Approach to Graffiti and Street Art Conservation” Plowden & Smith. (2019)

García Gayo, E. “Street Art Conservation: The drift of abandonment” SAUC Journal Vol 1 No 1. (2015)

Hoagland, S. “Art or Awful: The Conservation of Graffiti”. National Trust for Historic Preservation: Preservation Leadership Forum. (2019)

Rainer, L. “The Conservation of Outdoor Contemporary Murals”. The Getty Conservation Institute Newsletter, Volume 18, No. 2. (2003)

Santabárbara, C. “Street art conservation: beyond mural restoration” Opus n.s. n. 2. (2018)

Smith McNally, R. and Hsu, L. “Conservation of Contemporary Public Art”. Conservation Perspectives: the GCI Newsletter. (2012)

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