I keep them in the contrainers that it came in. I store them in the basement the temp is around 50 degrees year around.

I store one pounders in plastic "Sportsmans Dry Boxes". They are kept in my shop. (Insulated room, H/AC when I'm working-not at other times) I put "stickies" on the outside with the powder types stored in each box. Works for me...

8 pounders I store on the floor at the back of a closet and pour them out a pound or less at a time. The pounders just sit on a shelf over the bench.
I would think a frost free fridge set on 40 or 50 degrees would make a good storage locker.

You just might want to put flapper or blow out styrofoam vents on that fridge if you do try it. roger

Original cans in an old wooden dresser in the gun room. I'm still loading from cans of Unique and Bullseye that I bought in the early 1980's.