As long as it has a top...
I bought these tiny containers at Mitsuwa, a Japanese marketplace, a couple days ago. They are soy sauce containers used for bento boxes. That is actually what I bought them for, but I was trying to organize new purchases and found I had no containers available so I figured, hell, why not? I used two to store stud stoppers.
BTW, soy cause containers come in the damn cutest styles. The Japanese really know how to mix functionality and aesthetics. The ones here are blue and pink and are shaped like pigs.
It fit all but one of my packets.
That's not even all, the packet came with wing/eye stickers to decorate the pigs.