I don't know if it's a coin or just something coin-like but I got it in the world coin bin at the LCS. It's small and either aluminum or tin. It says 10 on one side and I see an F and M on the other side. Possibly it's toy money but I don't know.
I looked around a bit, and couldn't find anything similar. I assume it's exonumia rather than an actual coin due to the simplicity and lack of identifying text. Some merchant and livestock tokens look similar. If I had to guess, I'd say it's an old game piece or play money token.
It's "one thin dime"; play money minted from 1949 to about 1964 if memory serves. There are numerous series of these and some are actually dated. Older ones are tough. I'm not sure what's going on with the reverse though. The "F" should be an "E" from "ONE" and the "M' from "DIME".
If you can't find it I will check it against my collection. All of them I've seen say "One thin dime".
Most people would be amazed how many tokens and medals from the 20th century have no surviving examples. This stuff was made in huge quantities but has suffered surrealistic attrition. Most of it wasn't collected and the attrition on even something popular like CA good for tokens is 100% for most issues. Those which survive usually have several hundred examples because the entire surviving mintage was saved by the issuer to assure he wouldn't have to redeem them. Very few of the older "thin dimes" exist in Unc and some dates I've never seen but almost certainly were struck in very large numbers. A lot of world modern coins have suffered the same fate; they were deemed too common and too unimportant to collect.
It's interesting to think how some things that were made in such large numbers might not have been saved. One of my favorite things to do with coin buying is to look through junk bins because you really never know what will turn up. I feel the same with garage sales.
I've always had a hoot with the oddball stuff. I traveled all over the country looking for coins in my many specialties and always ask if they have a unidentifiable box. They often will bring out some strange and exotic stuff that i still can't identify. Usually they'd sell it pretty cheap. I just put stuff together that looks alike until there's enough to figure out what it is. I still have hundreds of items that are unclassifiable. My favorites in this were telephone tokens. I actually collected these for a few years until I knew what they were because one said "good for one telephone call" on it. A lot of collections were born from all of these oddballs. Most aren't terribly esoteric but belong to categories that are hard to identify unless you have a reference point. Lots of tokens have nothing but a fancy letter or number on both sides. Now days you can get info on most of this stuff online but that sure wasn't true even 25 years ago. Nobody really knows what has survived and what hasn't. My rule of thumb has always been if you don't see it then it probably doesn't exist. But I might run into three of the same thing and they might be the last three in the world. Early play money is tough tough tough. It and tax tokens are among the last frontiers. Of course there are books even on the tax tokens now but they are incomplete, don't list significant varieties, and don't give any idea of how tough the Uncs can be. These are effectively US coins but there are only a few hundred collectors. It's a big world out there. There are lots of fun and exciting things to collect that are quite scarce or unique but cost almost nothing at all.