When ever I go to businesses I always check those machines. I do find foreign coins. And I find silver coins. Those machines reject silver.
I have been collecting coins since 1963. In 2010, I was able to start ordering boxes of halves from one bank. Another bank ordered me boxes of cents, nickels and dimes.
When I got finished with the boxes, I would take them to a different bank (that had a coin machine) to deposit. One day they saw me parking in front of their front door
and as I walked in with my bags of coins they had already opened the machine so they could replace the bags when they got filled. The reject system wasn't working.
I reached up into the reject and was able to get coins come out. Going through them I found an 1820 Large Cent. It was in VG condition. That bank does not have those
machines any more. I now have to wrap them to deposit and get my cash back.