When you find a coin like this, ask yourself, does the coin show obvious signs of mutilation like scratch marks or bends, does it have marks where the metal has been smeared by force, is it smashed to the point that it isn't perfectly round anymore, and is this something that would have happened during the minting process. Learn how coins are made, learn the whole process so that when you see a problem with a coin, you can run through that process in your head and know whether or not it could have happened at the mint or most likely happened on it's journey through circulation.
