Bottle cap
I’m talking about that metal thing on top of bottles, real glass bottles. Here in the US, there are a lot of twist-off bottle caps, unlike the ones I grew up with in Nigeria. I remember needing to carry a bottle opener in my bag if I could—just the cheap metal kind that always hurt to use. I remember saving caps, especially as a kid, mostly so I could get the rubber lining out of them and use them in play.
The best caps were easy to pick the lining out of; a little old, sometimes a little bent or bruised. I think I washed them sometimes, to get the gross dried drink off, to maybe make it easier to get the lining out.
The plastic lining usually became one kind of thing: pancakes for my dolls. That is all I can remember when I handle a cap, when I stack a handful of them in front of my monitor.
Oh, and one more thing: the bottle caps usually became plates.