I found a silver dime in a Coinstar, early year Roosevelt I need for my Whitman book. The other coin machines suck up the silver, unless it is foreign.
Most vending machine will reject silver coins. But people aren't likely to just leave them in the coin return.
I was thinking coin machines but true, vending machines reject silver coins. I have a silver quarter someone was trying to use in a soda machine and needed another quarter, I ended up with the 1964 quarter.