Every couple months I go through my common rookie card and common inserts boxes for any player who came out of nowhere to be an everyday player. I have dozens of common 2011 Allen & Ginter's and normally I never really looked at the backs, but I got to Papelbon and put him to the side because he shouldn't be in my common box. My son looked at it and said, "dad, why did you write on the back?" I turned it around and was amazed I didn't see this before, a handwritten numbered Bazooka back. This Papelbon on COMC is currently priced for $50. For this vary reason is why I go through my boxes a few times every now and then, you never know what can slip through the cracks or a card you may have missed!
You never know where you will find treasure, it could be in a dime box, or even in one of your own!