Thanks for the replies y’all. All the suggestions I have been offered have been helpful. You’re right about the convex, I am just a teensy bit dumb at times. As for the metal I am not sure, as I don’t have it on me. Since I have found a good number of buttons, I am not against cleaning. Do any of y’all have tips for cleaning buttons? If I can clean it and there’s something interesting I will post pictures. Thanks!