What do you mean, "freezers don't work"?  Yes, they do, as has been
well documented in the literature.  But not just any old freezer.  Frost-
free models are not suitable, as they get rid of frost by cycling warmer
and colder.  Chest types work better than uprights.  For effective zapping
of insects, you need to reach -20 C, which is a tad colder than some
freezers reach, though most can be adapted to do so.  Please refer to

Strang, Thomas J.K.  1992.  A review of published temperatures or the
control of pest insects in museums.  Collection Forum 8(2):41-67

Florian, M-L.  1990.  Freezing for museum insect pest eradication
Collection Forum 6(1):1-7

Another approach is to use anoxic (low oxygen) environments, especially
for freeze-sensitive materials.  Perhaps someone more familiar with these
techniques than I am can provide references.

Skeletons prepared in our bug room are routinely bagged and frozen to
prevent insects from being introduced into the museum.  It adds a few
weeks to the process, but what is that compared to dealing wtih a pest
problem?

John Simmons
Natural History Museum, University of Kansas
[log in to unmask]