I am not sure you can get most of the curl out. I shot a couple of rolls of OLD TriX I had around. They were dried hanging with weights, the negative strips are still VERY curly. In a neg sleeve I put them under a couple of catalogs for a few months, they are still curly.(posted 8836 days ago)As to developing the old film, I would try it. I would expect that longer development would help. If you really think that there might be some images you really want, try a clip test.