Just sell them to any of the online gift card buying websites like RAISE.COM, CARDCASH, CARDPOOL and 20 others.
What if they are purchased from stolen cards?
Sites that buy your giftcard have security in place to charge your card if the balance is stolen or dealing with fraud.
Each site that does offer any payment during check out will ask this of you provide credit card on any of these plateforms. I`m not too sure about raise since thats more of a P2P seller type of deal, but I`m sure raise has way of dealing with fraud as well.