Hello. I mentioned in my introductory that I had inherited some items from my mother's estate. I found several film canisters, a couple being gray metal and another metal that is Kodak branded if I remember correctly. My questions are, how do I know if this film has been used but not developed? I haven't opened the canisters in fear of ruining the film if it has been used. These canisters come from before 1970. Probably the mid 60's up to the first two months of 1969. Also, if they have not been developed, what are the chances of them still being good? They were kept in a dresser drawer in an air conditioned house.