I use coin envelopes. They are a little smaller than 2x4, with a flap on one end.
When doing load development, I throw charges into them, usually 5 of each charge and write the charge on them, and stand them up in a box. I do not seal the flap. I write the charge on the envelope. Next time, i stroke out the old charge and write a new one.
For field work I seal the flap and carry envelopes in my pocket.