Pest & Mold Control methods in Museum Storage

1. 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, conservatour@msn.com

2. 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.
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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...."

3. “Freeze Em or Fry Em”
Wool pest eradication at Sinclair Community College

4. 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.
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"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.)
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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 darkpigmented fiber end a "bleached" area will be found resulting from pigment
loss due to heat under the kindling point of fur."
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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."

5. Insect damage
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"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 microorganisms, 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.
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Hair stubble appearing slightly above or flush with the surface of a "naked" patch of skin is
another clue to concentrated insect damage."...
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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.
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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.
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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.)

6. The Moth / Beetle Pest types:
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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

7. Vacuum , Heat & Sun then Vacuum
Jennifer & Student Intern

8. 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.

9. Mold or Air Space

10. Surface treatment of Mold
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If you see black spots on any of the surfaces then it is guaranteed that there is a
drainage problem.
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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.
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Prepare area for cleanup.
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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.

11. Humidity & Air,
Painting
Flip File Storage illustrated

12. TO REMOVE MOLD FROM HARD SURFACES
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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.

13. HUMIDITY, STORAGE & PEST TREATMENT in Bhutan
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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.
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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.
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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%.
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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.
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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...
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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.

14. Pest or Mold damage

15. HUMIDITY BUFFERS
include silica, terry towels, old sheets/ cotton, cheesecloth
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. 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.
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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..
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. 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.

16. Equipment needed for heat treatment

17. 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.

18. Boxes, Shelving, Fans & Dehumidifiers

19. PEST TREATMENT
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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.
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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.
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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.
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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.
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Jennifer Hein