A while ago, someone gave me about 8 rolls of long expired (I'm guessing around 30 years past date) Kodak plus-X. I decided to shoot a roll with my panamate to see if the film was still useable. I developed the roll in HC-110 (dilution H) for about 10 minutes, and I was surprised to see that the negatives were quite ok. There's a lot of base fog and the grain is pretty big, but the negatives were easy to scan.