Banknotes, when playing Guess The Grade.
As you go along your collecting journey it is almost impossible to NOT end up with a few duplicate notes, whether do to buying a bulk lot that contained a note you already owned, upgrades, winning an auction with a lowball bid, you purposely wanted a second note or you were running up the bid and got stuck with it. Ahem! No matter the reason I really enjoy having duplicates as it give me an opportunity to further study and learn about the note. My m