Chances are you received a gift card over the past few days. And there may be one or two that are useless for you. Now you can turn that useless gift card into airline miles. United Airlines is offering to buy your unwanted gift cards and exchange them for actual award miles through the airline. United will buy gift cards from many major retailers like Best Buy, Starbucks, and Walmart, and those you’ll probably never spend at places like Hot Topic, the Cracker Barrel, and Yankee Candle—basically, any of those gift cards sold in grocery store aisles for people who had no idea what to get you. United will even accept any gift cards to other airlines like American or Southwest. If you haven’t already, you’ll also have to set up a MileagePlus account with the airline and fill out an online form with your contact information. Next, look up the retailer of your gift card on United’s website to make sure they actually accept it. Assuming they do, enter the value of your gift card on United’s site, and United will then convert that value into award miles. You can preview this number before accepting, in case you decide to reconsider. If you are opening a new MileagePlus account, it will need to be active for at least 90 days for you to exchange your gift cards, meaning you’ll have to sit tight before receiving your miles.