My father gave me all of his firearms and accessories (but one) when he turned 80 or so. He had a couple of cans of powder dating back to the early 70's stashed away. Used one with no issues at all and the other burned up on the 4th of July for my step-kid. Stored in a box tossed from closet to closet that had moved 5 times and survived in fine condition. Roughly 36 years or so with no humidity control.