I dump my coins at a bank with a coin counter in the lobby, next to it is a trash can. I look inside every since I started finding coins in the trash!! They are always foreign coins and never worth much, but throwing away money makes no sense. I usually find Canadian coins but also, Euro coins, Mexican, and Caribbean.
I am not surprised about find money in the municipal trash. I read an article that in Germany they are digging up their landfills to extract the metals that have been dumped their over the years. A generation of dumping consumer electronics has left them full of copper, steel, aluminum, nickel and even PMs. The yield per ton of trash searched is greater than the yield of most current operating mines!