How to Clean the Magnetic Strip on a Card. Credit cards can get grubby. Think of all the places your card has been-bars, ATM's, grocery stores, malls, Starbucks. It is bound to need some cleaning now and again. To safely clean your credit card so it will swipe as well as it did on that wonderful day you got it in the mail--virginal and sparkling clean--follow these simple steps.
Rub your card with a plastic bag. If your card is not working, sometimes just rubbing it with a plastic bag can make it work again. The plastic will lubricate the rough spots on the magnetic strip and it will begin swiping properly if it was just a little dirty.
Wet the magnetic strip with water and the tiniest bit of soap (unscented, plain soap). Rub gently with a soft cloth (nothing abrasive) to remove or wash off the bits of dirt that may be stuck to your magnetic strip.
Rub the strip on a sweater. If your card has become misshapen, the rubbing motion of the sweater will warm up the card just enough to make it more flexible, enabling you to swipe it through the slot.
Bring out the big guns if the above methods fail. Use baby wipes. These suckers will clean off almost anything. If you don't believe it, just remember what they are designed to clean up! Not only are baby wipes are incredibly gentle, they are also extremely effective.