Hello Susan,

One possibility is boric acid.  I don't know about its usage with beetles,
but it works for ants, roaches and other parasitic/fungal infestations.  It
inflames the cuticles and tubules of the microorganism.  It is also used to
dust carpets for larvae, mildly abrasive to the skin.

Please bear in mind that this is only a suggestion and that you should
research its effects before using it on valuable objects.  Maybe an opinion
from a professional pest control company or a physician would be helpful.

Kim Humiston
Institute of World Cultural Studies
Cambridge, MA