I like to carry the Altoids (round metal can of citrus sours - not the mints) in my BOB. Plus, I like the idea of the small metal container. Been experimenting with using one for a minimalist PSK, but I'm finding the round shape is actually a bit akward to fill efficiently. I also have two each in the kids' bug-out/camping survival fanny packs. My children really enjoy them, so they are there for comfort, as much for some emergency sugar (dual-use, sort of). Trouble is they tend to "test" them once in a while so I need to replenish every few monts, but it's at least worth it getting them to pay attention to their packs every now and again.

Michael