Find some plastic test tubes with caps. My uncle has a Savage ML-10II muzzleloader that uses smokeless powder. He dispenses the loads with an RCBS Chargemaster 1500 and puts them in the test tubes until he uses them. They stay there for anywhere from a couple hours to months at a time, no problems with static, summer or winter.
Still happily answering to the call-sign Peetza.
The problem, as you so eloquently put it, is choice.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.