they can be delived but not mailed
You have to buy the pack of cards at any shop then upload it on to Club Penguin(u need to have membership if u want to buy stuff)
You can buy club penguin membership codes from the shop but unless you win one in a competition there is no such thing as a free club penguin membership code.
A membership that is unused
codes for dodo cards club penguin
It depends if its a membership card or a book or a code. So i would just keep it. -peanut3141