User blog:Nad331/What to do...

Book 10 in the 39 Clues series has just recently come out. I put a hold on it at the library and just picked it up a few minutes ago. However, I did not get the library edition, I got the edition with the cards. It appears I am the first one to use this book, because the cards are still there. My question is, do I keep the cards, enter the code and return them or leave them where they are and buy my own copy for the cards?