This!!I keep it in the gun cabinet. Long as the lids on snug its fine. As far as storage safety goes black powder is not half as bad as gasoline.
BP is only "explosive" when it has a source of ignition AND it's compressed. Meaning,, a can of bp won't "explode" if/or when it's exposed to a common accidental fire (as a house or garage fire).
Store BP on the floor, if your concerned , not on a shelf, because heat rises (right?)
Unless there is a direct heat/flame/ignition source,, the gradual rise of temp (even above flash point) changes the character of the sulfur content of the BP composition.
Without gettin real heavy science on ya,, the sulfur crystallizes and changes the whole matrix. The stuff will then go off like smokeless,, "foof", no boom.