I have come across some vintage (I believe 1960s) 1/4 inch acetate tapes that I would like to attempt to migrate for student research (and practice), but they have suffered significant degradation. They were stored in cardboard boxes, I suspect in unfavorable locations, possibly in garages or attics in a very dry climate. A few of them were left in a hot car in summer.
Upon inspection, one tape is so brittle that a small piece broke off immediately during inspection. I did not attempt to play the tape.
Another tape that was definitely subjected to heat was not brittle and appeared to have no interlayer adhesion. It did have a couple layers of uneven tape pack (where there was a layer pushed out of the rest of the pack). This tape played back with significant speed variations (sounded like extreme flutter and wow), and had some shedding. Both dark (maybe magnetic material) and white gummy deposit was evident on the machine. The calibration/test tape played back normally immediately before playing this tape.
Are either of these tapes recoverable, at least long enough for migration?
In either case, I am looking for detailed instructions regarding acetate tape restoration for my research, particularly treating brittle and/or tape subjected to overheating and temperature fluctuations. I see that the IASA literature addresses vinegar syndrome and brittle tapes, and it mentions that shrinking and warping happens if storage climate is too dry. I don't see detailed instructions for the restoration process to address these issues.
I have located AES papers and other sites referencing both a hydration processes and lubrication with LAST. Would those processes be appropriate in either of the above circumstances? Are there other solutions for the above symptoms? If so, where might I find credible resources with detailed instructions to try these restoration processes?
I look forward to any recommendations.