Does anyone know if there is some place to check if a code has been used or not without entering it into the game? My sister mixed up three of my Insider badge cards so now I have no clue which are good and which are not, I don't want to enter them in and loose them but I can't trade them until I know which ones are still usable:confused:

Trade one give it to them and ask them if it works then if they say it does not then send them a new one and repeat.