A bubble gum.
I thought of it just the wrap of a bubble gum. But I wasn't expecting that it's with the bubble gum that I've chewed. Sounds weird but I was still a young guy when it happened.
But how come that a Chewed Bubble Gum stays in your wallet ? if that is a Unchewed that is reasonable but what you have >?lol that's really weird

Cinema tickets - I usually keep them whenever I go to the movies with my partner (lol very sentimental) .
But that's now weird at all because i also have some specially when i was in secondary or college .
and i will not have them now because for sure my Wife will Kick my ass if she finds one in my wallet