The black strip on the back of your credit or debit card is magnetized and stores information about your account. When the strip is swiped, the merchant accesses your private information so you can make your purchase. If the magnetic strip is physically altered or demagnetized, the "swipe and buy" process cannot be completed. Keeping your card away from items that will damage the card can help protect the strip. Discarding your old cards properly minimizes the risk of thieves extracting the information embedded in your card's magnetic strip.
Store your credit card in your wallet or a credit card holder instead of loose in your purse or pocket. Magnetics of any kind, such as the clasp on your wallet or pocketbook, magnets on and inside your refrigerator and in other areas of your home can erase the secure information about your account that is encoded on the magnetic strip. Keys in your pocket can also scratch the strip and lead to difficulties.
Switch to a wallet that does not have a magnetic clasp or closure if you have recurring problems with your credit card strip. Though the magnetic clasp may not seem strong, according to CreditCards.com, it could be enough to damage the strip on your credit card.
Place your credit cards in the same direction when storing them in your wallet or other holder. Putting two different credit cards back to back, with the magnetic strips touching each other, can demagnetize one or both of the strips, rendering them useless.
Keep your credit card in a paper or Tyvek plastic sleeve to protect the strip against physical damage and demagnetization. Some banks provide paper sleeves to their customers. You can also buy sleeves commercially to protect all of your cards.
Cut up an old credit card that you are no longer using, rather than just tossing it into the trash. According to Your Credit Network, an online credit card information resource, even if your account is no longer active, the magnetic strip holds secure data about you and your spending habits. Hackers can potentially access the information if the strip is whole.