I remember playing quarter machines in the early
seventies that paid real silver dollars. Some machines
paid a single coin and others paid one, two, or five coins by
lining up three Morgan dollars with those numbers. The idea
was to unload silver dollars that the clubs were no longer
using. The reason for the stickers was they didn’t want
people bringing in their own coins. The stickers were just
about impossible to remove. I know because I tried.