I've never found anything outside of a hair, but the one that sticks out happened when I was in 4th-5th grade.
Me and my friend were eating lunch, when one of us (can't remember who) finds a hair. It wasn't that big of a deal, but we decided that we wanted a new one. So we go up to one of the lunch ladies, ask for a new lunch, and show her the hair. She takes the hair from us, throws it away, and tells us to sit back down. We tell the principal about the hair, who asks them about it. They deny it, accuse us of lying, and say that we are trying to get them fired. The lunch ladies then decide that they can be assholes to us as long as we went that school.
I hated them.