I have a small box filled with old negatives. Most of which are very tightly curled up on themselves and look like small cigarettes. They are about 60mm wide by various lengths. They may be 120/220 but they are all cut to individual photos so who knows.
Some could be unwound enough that I was able to flatten them (somewhat) between books, but some just refuse to unroll and a few break when forced.
I need some way to relax the negatives enough for me to scan them between two sheets of anti-newton glass.
I suppose some of it could possibly be nitrocellulose but none of it has deteriorated like I've seen in some photos of it. However, this is another reason I'd like to finish this project and get it out of the house.