Here is a thread on Arfcom some may be interested where an old 8# jug of powder self-combusted. http://www.ar15.com/forums/topic.html?b=6&f=42&t=281373 On the otherhand, I opened a 1# canister of Unique last night that was given to me a few years ago. The old owner bought it at least 2 decades ago. The powder was black as coal and had no smell. I put a match to 5 grains worth and it went right up. All 15 rounds of 45LC I loaded up shot great today. BTW, the price tag on the canister is $5.60!