You can donate it to American Express, or you can donate it to charity. You can’t use it along with another credit card to make a purchase, despite the fact that restaurants will take more than one credit card, if your party is going “Dutch treat”.
New Jersey’s government has another idea for gift cards’ unused balances: claim it for themselves.
It’s worth noting that’s $17 million in forfeited gift card money in New Jersey alone.
Tell your family and friends that when it comes to American Express gift cards: forget it--that you’d rather see the unused balance going to them than to donate it to American Express or the government.