One that I listed on eBay years ago - I think I paid something like $60 for this, and I still think I got a good deal, but I doubt I'll ever find a buyer for it. eBay description (no longer listed there, and this is not a for-sale post! Also, I'm thinking VF details is probably more accurate):
Not a coin, but a token. This was made from iron which was recovered from the wreck of the CSS Virginia, the Confederate ironclad. It's made of iron, so it's prone to rust, and this one got its share. Many years ago, this was listed as a Civil War token. It's since been determined that it was made in the early 1900s. Nice examples of this have brought $3,000 at auction. The worst deal I ever saw on one of these was a piece that had been certified, BUT it was rusting in the holder. The dealer noted this to the bidders, and offered to let those out of their commitment of you wanted to do that. Someone still paid close to $2,000 for it. Sorry, I would never do that. This one has not changed since I bought it many years ago. Still if it's a holder, there's only so much you can do for it without cracking it out. Here's another item that was made from recovered CSS Virginia iron, a miniture horseshoe still in the card of issue. It's in far better shape.
This is a zinc cent. I found it in our barn a few years ago. I can only identify it as a zinc cent but a few details that are still on the coin.
I'll take a rare authentic, holed coin over a nice counterfeit any day and I have some in my collection that had been jewelry mount coins. I collect rare 1700's Sicilian sliver Tari coins from the Palermo mint and some are so rare that you seldom see them for sale and the reason they survived is because they had been jewelry mount and not melted down hundreds of years ago. I despise counterfeit coins
The below coin of @H8_modern might have been halved to form a "Mizpah" coin. What is a Mizpah coin? It is a coin symbolically cut into two matching pieces, most often with a zig-zag line, then shared between two people. Each part represents their bond of love and loyalty between one another – typically when apart for a time. Although they are quite often worn as pendants, Mizpah coin halves are also utilized as rings, jewelry, keychains, or simply carried with pocket change. There is often a spiritual faith connection within the association, which stems from the fact that Mizpah (Hebrew word) means "watchtower", as seen in Genesis 31:49, which reads: “It was also called Mizpah, because he said, ‘May the Lord keep watch between you and me when we are away from each other.’” - NIV (1985) So, perhaps (and I fully admit this is speculation) a couple married in 1937, and the husband carried half of the coin in his pocket while his wife carried half in her purse. Going just a step further into the realm of possibilities, it could be that one went away to war in WWII.