As part of a large-scale move of our older archaeological site archives to off-site storage, we are intending to preventively freeze all out-going boxes of material. The material itself is not inherently vulnerable to pests: pottery sherds, both high- and low-fired ceramics, glazed ceramics, ceramic building materials including glazed tiles, stone and flint objects, animal bone, and so I have no experience with freezing this type of material nor am I finding much in the literature to help.
However, carpet beetle has occasionally been found to affect the cardboard boxes the material is stored in, and we want to avoid inadvertently transferring this to the receiving store. Constraints on staff time preclude us from pest-checking every box, or removing the contents from boxes prior to freezing the boxes alone. We will be hiring a freezer container, which is capable of reaching -30 degrees C - once this temperature is reached we intend to leave the material for 1-2 weeks and then allow it to defrost before transport to the off-site store. Currently, most of the materials are sealed inside polythene (polygrip) bags inside the cardboard boxes, which should offer some protection to the materials during freezing. Has anyone carried out a project similar to ours before and what were your experiences? Are any of the archaeological materials listed above likely to be adversely affected by the freezing / thawing cycle? We are particularly concerned about the glazed ceramics and the possibility of glaze "pinging off"; and perhaps also the animal bone assemblages. Another concern is avoiding damage to markings on boxes and adhesive barcode labels adhered to the boxes - would these be adversely affected by freezing and would it be advisable to seal the boxes themselves in polythene prior to freezing? Any advice/suggestions would be gratefully received! Naomi Bergmans *Curatorial Assistant (Archaeology)* Oxfordshire County Council, Museums Resource Centre ****** Unsubscribe by sending a message to [email protected] Archives through August 2016 at http://cool.conservation-us.org/byform/mailing-lists/cdl/ Archives from September 2016 onward at https://www.mail-archive.com/[email protected]/
