Pest & Mold Collections Care
based on M.L.Florian and other scientists research
“Freeze Em or Fry Em”
• Jennifer Hein, M.A., M.S.
Preservation Conservator, [email protected]
Excerpt from J. Hein’s Thesis 1997 FIT-SUNY Insect Freezing
1986 LCN, Fall Vol. 3 #1, pp. 1-9
"The Freezing Process -Effects on Insects and Artifact Materials“
FLORIAN, M.L. E.
• Freezing Procedure:
• 1) "When using a chest freezer, infested artifacts should be bagged in airtight polyethylene film, and partially evacuated...
• as soon as the artifact is in the bag, insects will respond to the environmental change and try to escape, therefore seal immediately.
• 2) When using a chest freezer, if the artifact is large (ie. furniture) pretreated silica gel or absorbent materials can be included with the artifact in the bag to absorb the excess water due to cooling... ...
• 3) Bagged infested materials should be kept at room temperature until placed
• in the freezer.
• 4) There should be adequate air circulation around the artifact...
• 5) The minimum temperature...is -20'C / 4'F.
• 6) The times span at the minimum temperature (is) ...48 hours.
• 7) A slow rate of thawing is desirable.
• (From freezer to refrigerator if possible)
• 8) It is desirable to immediately repeat the freeze-thaw cycle.
• 9) ...Do not remove the bag until the artifact has reached room temperature and there is no condensed water on the outside of the bag...."
“Freeze Em or Fry Em” Wool pest eradication at Sinclair Community College
MOST COMMON Wool / Fur PEST & their Lifecycles,
Excerpt from JHein FIT-SUNY thesis
-ID- pests & fur damage
1966 Oct, CALIF. Agriculture Exp. Sta., Ext, Circular #514,
"Analyzing Fur Damage with a Microscope"
SPENCE, ROY J.
• "Two to four select animal skins that are finished to make up a small fur
neckpiece such as a boa or a twist can be priced upwards of four figures. ..Bare areas on a fur usually direct suspicion to feeding insects...However, "Snap" diagnosis of insect damage can be made only if their living or dead bodies, fecal pellets, cast skins, or other obvious signs, such as fiber particles are apparent. ...(Other causes should be considered.)
• Fire - To make a diagnosis, tweeze out or cut a damaged guard hair of the greatest length and diameter from the fur at the skin line. Guard hair is composed of the longer fibers of fur which tend to protect and conceal the shorter fibers, or undercoat. ...Immediately beneath any burned dark-pigmented fiber end a "bleached" area will be found resulting from pigment loss due to heat under the kindling point of fur."
• Wear - "Evidence of gradual wear can be found at the elbows and collar of a fur coat. Abnormal wear can occur on any area that is exposed to accelerated friction."
Insect damage
• "Clean" fur lacks these (food) supplements and must be contaminated with a certain type of soilage, food spillage and related nutrient sources before a normal insect life cycle can occur. Contamination is inevitable; it is caused by perspiration, body oils, or ...even air-borne micro-organisms, that synthesize certain elements of nutrition....once exposed to air, or even brief handling, it is sufficiently contaminated to provide an acceptable diet for fiber-feeding insects.
• Hair stubble appearing slightly above or flush with the surface of a "naked" patch of skin is another clue to concentrated insect damage."...
• Chemical damage - Animal hair is keratinous (nitrogenous substance forming a large part of hair, nails, claws and horn ). It is difficult to destroy; strong acids will not break it down and most strong bases will do no more than soften or ...bleach it.
• Without the microscope - "Careful observation with the unaided eye may reveal fecal pellets and cast skins in undisturbed insect infested fur. Shaking may dislodge most of them, but a few usually sift deep beneath damaged areas, with some clinging to the sides of fibers. The pellets are always the same color as fibers fed upon." ... Many insects are capable of shredding fiber rather than actually feeding. Such insects include silverfish, cockroaches, crickets, earwigs, and certain moth larvae, which sever fibers for use in constructing cocoons.
• Damage by these and other insects is incidental, and attention here is focused on important Lepidoptera (moths) and Colepotera (beetles) which are known to feed on fur and other keratinous substances as a source of food. (This resource contains illustrations of the insect types discussed.)
The Moth / Beetle Pest types:
• 1) Lepidoptera, webbing clothes moth, Tineola bisselliella (Hummel) Life history - 1 month to 4 yrs.,
• life cycle 65-90 days
• 2) Case-making clothes moth, Tinea pellionella (Linn.)
• Life history- similiar to clothes moth
• 3) Coleoptera, black carpet beetle, Attagenus piceus, (Olivier)
• Life history- up to 639 days to develop, as many as 20 molts or 258 days and less than a year.
• 4) Furniture carpet beetle, Anthrenus flavipes Le Conte
• "often found infesting woolens, carpeting and fur in the upper stories of high buildings."
• Life history - 10 - 13 weeks if favorable, at room temp. from egg to adult varies from 149 - 422 days.
• 5) Varied carpet beetle, Anthrenus verbasci (Linn.)
• "thrives on dead animal carcasses, dead insects, bird's nests, plant products (Natural History) Adults are pollen-feeders and enter homes during the spring and early summer
• Life history - less than one year to as long as 1 1/2 years.
• 6) Common carpet beetle, Anthrenus scrophulariae (Linn.)
• "This species runs rather than crawls. ..feeds freely on carpeting, ...furs, feathers, leather, brushes, silks and mounted museum specimens as well as pressed plants. "
• Life history - egg to adult is 94.5 days aver. or 89-108 days
Vacuum , Heat & Sun then Vacuum Jennifer & Student Intern
BLACK MOLD TREATMENT
Typical locations:
Partial stone or block basement walls
Plasterboard wallboard in a damp area
WHY TREAT?
Mold digests organic materials. The 1990 Intl. Conservator’s / ICOM entry states mold growth can take place at 61-68’ F / 19’C and a RH/ relative humidity level of 55-60% which is basically room temperature on a rainy day. Leather & wool are the most affected materials.
Mold growth can be controlled by drying the environment.
COLORS in order of degree of danger: White, blue or green, brown then black.
SIZE? Typically, the larger the circumference of the spot the more active the mold.
Mold never dies, it just dries up & shrinks in size. Moisture reactivates it to bloom.
Mold or Air Space
Surface treatment of Mold
• If you see black spots on any of the surfaces then it is guaranteed that there is a
drainage problem.
• Leather Conservation scientist, Calnan states,
• “The simplest way to prevent fungal attack is to control the environment. “ LCC 1985
• Try to improve drainage outside that side of the wall.
• Install a dehumidifier in that space.
• Raise the heat if possible in the space.
• During winter, use a spray mist to apply the bleach solution to the affected area.
• Spray area weekly/ biweekly until drier over a 1-2 month period.
• Bleach solution should be 50% water, 50% sodium hypochlorite , .5% bleach.
• Prepare area for cleanup. – Wear safety mask, disposable gloves, & washable clothes or smock.
– Lay down layers of newspaper on floor near wall.
– Cover 3-D objects in storage nearby with plastic to protect from contamination.
Humidity & Air,
Painting
Flip File Storage illustrated
TO REMOVE MOLD FROM HARD SURFACES
• First, use a paint scraper to remove larger debris.
• Brush large components off the wall. Roll up in newspaper. Dispose in trash bag.
• Next, use wire brush to remove smaller debris in crevices, roll up newspaper. Dispose of in plastic bag.
• On plasterboard the wire brush will break out the wallboard so brush slowly & observe results.
• RE - SPRAY with bleach solution periodically until the situation seems controlled.
• CONTINUE to use dehumidifier. Monitor.
• Install a box fan in the area to improve the air circulation in confined spaces.
• Keep area vacuumed well. Only use a HEPA- Rainbow or wet dry vacuum but be careful not to contaminate. Other vacuums re-circulate the mold spores through the bag or the exhaust.
• Clean vacuum well after use with mold.
HUMIDITY, STORAGE & PEST TREATMENT in Bhutan
• The recent exchange on CIPP regarding the use of storage containers and dessicants in less controlled HVAC systems began this discussion with non air conditioned latitudes.
• This is also good for any damp humid historic collection without controlled air conditioning in recent historic collections I visited in any middle Latitude. Decisions for storage should depend on the efforts of the collection to keep the building temperature & humidity controlled. If there is little or no air conditioning then I would work with these basic ideas.
• Extreme Humidity & Temperature Problem:
• textile storage and pest control in Bhutan, changing in late October after the Monsoon season. Basic textile conservation, upgrading 200 non-rolled textiles in storage at the National Textile Museum, Bhutan, India. currently, piled on open shelves, some in zip lock bags to isolate or prevent infestation. Vast Temperature and humidity fluctuations,40-50 degrees between summer and winter. monsoon season from May-Sept, RH is around 90% RH and up to 110%.
• MY OPINIONS AND ADVICE
• system of dessicants? silica gel? Any other solutions? In very damp environments, I would never use corroplast boxes. These are best prescribed for Air conditioned western hemispheres. The humidity builds up inside much like a plastic container or box. When people use these sealed boxes or plastic here I ask them to insert an old towel to absorb the extra moisture. It acts somewhat like silica, costs less and is washable.
• THE TRAY METHOD is best in humid environ because it breathes. The Africans used open basket like trays on stick support shelves in a hut and it actually worked well. They had a lightweight dust cover...
• The top cover is for dust. But it is also important to add a humidity buffer to each container if it is sealed, even a letter size box and especially an enclosed box with no hand holes. So I suggest the cheaper letter size office type archival boxes in less controlled environs.
Pest or Mold damage
HUMIDITY BUFFERS
include silica, terry towels, old sheets/ cotton, cheesecloth
• . This is a list of any absorbent cotton material, the less dyed and processed the better. This may be easy to find in Bhutan. Include some type of absorbent and in the dry season it will dry out. In the wet monsoon it will hold moisture so it needs to be off to one side in the box....or tray.
• Western Hemisphere Box Standard: acid free board boxes and silica gel containers in each box. This does not prevent the boxes from becoming damp in high humidity. I dislike corroplast box cubes and plastic bins because they are fairly air tight. These do not let the environment buffer humidity changes. The barrier material of the container acts as a moisture barrier to keep humidity in and things mold more quickly. Better idea - any box preferably archival board box,Best is the letter or legal boxes with the hand holes in both sides. This container allows some air ventilation and you can still control the interior space inside like a microenvironment. Extreme 3rd world Example: South American & African efforts in warm buildings. The tray method is best in humid environ because it breathes. The africans used open basket like trays on stick support shelves in a hut and it actually worked well. They had a lightweight dust cover..
• . TRAY METHOD: My revised version is to store things in trays then criss-cross them. Purchase sturdy archival boxes that can be separated in two trays then cross stack them. This gives a form of isolation with some ventilation to allow the extra humidity to dissipate. The tray method saves you money to buy 50% less boxes and allows for ventilation. With the tray method you use the sturdiest box tray as the bottom one, then stack until the shelf is full. As a dust cover, Acid free tissue, ragboard, old sheets, pillowcases, cotton fabric of any kind, cheesecloth or terrycloth can be layered as a top dust cover, and yet it breathes. As per box types, when humidity and pest are an issue I prefer the thin compressed board with the metal edge, because corrugated tends to become a pest condo after 1o plus years in humid environs. If you do get the metal edged boxes save the container and use these with a barrier liner on the non-archival base since these are usually longer and are good for silk that should not be folded. Metal edge boxes do not ship flat, so if accessibility is a problem, choose any two piece box.
Equipment needed for heat treatment
BARRIERS
• Corroplast boxes make a good barrier on a wood shelf or if items
are stored in a basement that may flood, so good for Disaster control. On every wood shelf you need a barrier so the wood does not stain, for the same basic reason archival boxes were created. The acids from boxboard or wood naturally leaches into the more absorbent material.
• SHELVING type of shelving- try to get baked on coated metal.(Never repaint)
• FANS Get more fans and if possible a dehumidifier. In high humidity, it takes a commercial grade in a fairly enclosed room and it will run 24 hours a day, which requires a lot of electricity. Air circulation is the key to success in any humid environment. Place fans near all windows and doors....even when they are closed.
Boxes, Shelving, Fans & Dehumidifiers
PEST TREATMENT
• The last thing is for pest treatments. There are 2 methods" Freeze em or Fry Em/. Since you will have heat I will only explain this. To check for pest evidence, take object over to a clean area and hang on clothesline, tamp or slightly beat. See if shell or minor frass (sand) drops out. If so heat treat.
• I have 4' X 6' plastic bags on a roll, but cheap plastic drop cloths work too.
• Lay plastic flat, lay old sheet on top. Place object as thin as possible on top, fold over plastic and sheet then evacuate air from the bag and tape with duct tape. Then fry like on a griddle. Lay enclosed package out flat in sun. Depending on heat and fragile nature of object, leave 1/2 hour to one hour on each side, turn and repeat time for 2nd side. Bring inside, let return to room temp, preferably overnight, then unbag. Take object over to a clean are and hang on clothesline, tamp or slightly beat, see if more shell frass or minor frass drops out.
• Doesn't matter at this point you are only trying to kill the larval stage of minor pest.
• Vacuum on both sides if possible or at minimum shake outside. This process should slow down pest problems by about 75%, according to CCI test/ Canadian Cons. Inst.
• Hopefully this will clarify what we discussed. Feel free to call me with questions. You can reuse the bag, but I start with the larger things and cut it down. The problem is keeping it flat while you enclose it with tape.
• Jennifer Hein
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