I got 30 year old stored in garage in Houston for at least 24 years, in my case it is still good. Smell it first, then look for discoloration and fine dust. If it passes, I would do a test load.Since I haven't been loading for a few years, I have several metal cans of the DuPont power of various numbers. I just hope that it hasn't gone bad. I can still tell by smell and color, right?