I know this might sound odd, but has anyone thought of using Parafilm??? We use it in my laboratory for temporary seals on glassware and petri dishes. It has wonderful stretching properties, and has a tackiness to it when stretched.
"Masking applications:
Parafilm will conform to any surface and fill in the tightest corners. It lifts easily and leaves no residue behind on the surface being protected. It is the preferred material by many for model masking. Cut out a thin strip from either the 2" or 4" rolls and slowly stretch to about four times its original length and let it set for about one minute. This permits it to "stress relax" resulting in the development of a nice "tackiness" to the stretched material. The thin strip is applied to the surface requiring protection and masking. Using normal finger pressure massage it into a good adhesive situation with regard to the substrate surface. After painting, it will come back up with the gentle lift of a toothpick. Unlike a number of other masking agents, it will absolutely not leave behind a residue on the protected surface."
I know we're not using it for this purpose, but if it can be used for model masking, I'm fairly certain it would work in this situation. I'll have to call the manufacturer, since it is permeable to oxygen and carbon dioxide, but it should prevent whatever chemical reaction is occurring from damaging the surface of our prized possessions. That, and it's tackiness should hopefully prove to be a sound solution to the current problems.
Source: http://www.2spi.com/catalog/supp/parafilm.php