Hello, I'm not terribly new on currency collecting and value, but I recently got a 50 dollar bill with something I've never seen or heard about on it. On the back of the note on the right side it has a c a star and a z. I know it's not a star note, but was wonder why this would be on a bill, and if it's worth anything more than face value. If anyone could help me figure this out it would be greatly appreciated.
