1799 Corroded Coyote

The ones made of steel will start to corrode, fairly quickly. Especially if they were originally sold in an open-air market.

Had a visitor come into a coin club meeting a year or so ago; he'd bought some "American dollars" in Vietnam a few years earlier and wanted opinions on their authenticity. I had my rare-earth magnet with me at the time, but didn't really need to use it to prove they were fake; the details were getting hard to read because of the rust. I used the magnet on them anyway, which gave a very convincing CLANG. My magnet's still got rust flakes stuck to it.