I really like the hydapeak-style airtight thermoses (mine aren't hydropeak, but similar). Vials go in straight up and down in two layers of fifteen vials. I like to do three kits of the same thing per thermos when I can, so I can label the outside, inside, tuck a folded COA on top, pack with a few dessicant packs, and go about my business. If I have more than one type, then I don't store more than one of the same-colored lid in one thermos, include the coa's for everything that's in there, label the outside and the inside with what they are and what color the caps are, and bob's your uncle.