Pest management

Ken Myers <kenmyers1 [at] mindspring__com> writes

>Within a gallery devoted primarily to costume and textile items, the
>exhibits department of our museum intends to display as an exhibit
>prop a large bale of used clothing and other textile items which is
>being donated by the local Goodwill (approximately 6'X3'X3' and
>weighing 1400 lbs.).  Goodwill bales those donated items deemed
>unsaleable in their store locations. Knowing neither the
>"provenance" of the items compressed within the bale nor their
>condition (clean/dirty or dry/damp), I have some reservations about
>introducing it into the gallery environment if it might potentially
>be infested with pests of some kind.  We have wondered about the
>possibility of having the bale fumigated somehow but in initial
>telephone queries have had no success locating a source for this
>service.  In the absence of fumigation, as a minimum measure we are
>considering accepting...

I can certainly sympathize with your worries about letting such an
item go in to your institution unchecked.

For several years I worked in a Museum with a variety of
collections. We regularly acquired suspect material in the form of
agricultural equipment straight from barns, objects made from
un-tanned animals skins, wool clothing, carpets, etc.  We found that
a program of quarantine and inspection was very useful for
preventing unwanted pests.  When we found items which were infested,
or which we could not determine were not, we went through a freezing
routine to kill any insects.

I would recommend freezing over fumigation for several reasons. It
does not involve the use of poisons which could harm staff and
adversely affect other objects in your collection.  Freezing may be
considerably less expensive than fumigation. You and your staff may
be able to carry out a freezing routine yourselves without having to
seek out expensive consultants to do it for you.

Before you do anything with the clothing bale, however, I strongly
suggest you get it securely sealed in plastic sheeting. Sticky traps
may catch some insects as they exit, but a layer of plastic sheeting
will prevent them from leaving the object at all. Clear polyethylene
sheeting will allow you to see dead and live insects as they appear,
accumulating dust which may be frass and tiny fragments of loose
cloth which suggest that there is insect activity occurring
overnight when you are not there to witness it. Use heavy duty, wide
packing tape or duct tape to seal your plastic. If you are going to
freeze it, there will be condensation and other types of tape are
not up to the challenge.

In order to kill insects, you will need temperatures of -20
centigrade (just below zero Fahrenheit), which is a temperature
reached by meat freezers. Many insects are killed by rapidly
dropping temperatures, but will become dormant and survive freezing
if allowed to adjust gradually to the cold. For that reason, you
will have to make sure that the bale is well warmed-up before
placing into a freezer.  A day at room temperature should be fine.

Opinions differ about the amount of time required to freeze-kill
insects. 48 hours in the freezer, followed by at least a day in a
warm room, followed by another 48 hrs in the freezer is a pretty
standard routine. If you can leave the object wrapped up for several
days after the second freezing round, you can inspect for more
activity, as an added precaution.

Since you have such a large object, you will need to find a very
large chest freezer, a walk-in freezer or a freezer-truck. Try a
local university. They sometimes have large freezers and may only
charge you a small fee for use. Other options are commercial
trucking firms, although they may balk at placing old clothes in
spaces designed for food storage, and firms which deal with
water-damaged archival and material.

Valery Monahan
Assistant Conservator, Archaeology
Fortress of Louisbourg


                                  ***
                  Conservation DistList Instance 13:42
                Distributed: Wednesday, February 2, 2000
                       Message Id: cdl-13-42-015
                                  ***