I started this at USNM in 1995 after some research.  I gave a couple talks at ECN a while ago about freezing.  Minus 25C will kill anything we need to worry about.  No need to bag or repeat freeze - cellulose will reabsorb any moisture. But after freezing do leave drawers, etc. out for enough time for them to re-acclimate - don't open them.
We also talk about this in the Entomology Collections Management Workshop.

From: Entomological Collections Network Listserve [[log in to unmask]] on behalf of Brown, Richard [[log in to unmask]]
Sent: Tuesday, February 21, 2017 11:01 PM
To: [log in to unmask]
Subject: freezing drawers for pest control

We are receiving some major donations, some of which have had some dermestid damage.  We have regular freezers as well as an ultra-low freezer.  Does anybody know of adverse effects of putting drawers of specimens in an ultra-low freezer before the drawer is brought into museum?

-- Richard L. Brown

Mississippi Entomological Museum

Dept. Biochemistry, Molecular Biology,   

      Entomology & Plant Pathology

Box 9775 (100 Old Highway 12)

Mississippi State, MS 39762

PH:  662-325-2990

Cell: 662-694-0174