I found this is a small plastic button looking thing at an 1850's gold mining site near Sacramento CA. It is thin and bendy and it has a little bit of fabric through the middle of it. Any ideas?
If the plastic is sort of soft and bendable, it seems like I have had these on the backs of buttons/snaps, on either rain gear or covers for camping equipment. Just a fuss, my old eyes aren't as good as they used to be. Hopefully someone has the an answer!