Checking out at a store is usually a stress-free process. Your items are scanned, you hear the total, you swipe your card, you grab your things, you leave. But sometimes there’s a hitch in the process. Your card won’t scan! Not to worry. It’s a pretty common issue and it can happen to anyone. It just means something’s wrong with your card’s magnetic strip. How Does It Work? All debit and credit cards have a black strip on the back that contains little magnets which can be arranged in certain configurations to relay information. This magnetic strip, or magstripe, contains all the information your bank or a retailer would need to know about you in order to complete a transaction. This includes your name, bank account number, and expiration date, among other things. One magstripe contains three tracks that are each used for different pieces of information and data. Each track is .110-inch wide and your card typically only makes use of strips one and two with the third being used as a read/write track that isn’t standardized across all banks. Should I Worry About A Magnet Messing With My Credit Cards? Because the strip on your credit card is based on magnetic storage, yes. Magnets can tamper with the magnetic stripe on your credit cards, erasing the information stored there and rendering them useless. A test run by Cynthia Drake of Creditcards.com put 3 different magnets to the test: a refrigerator magnet, a stronger magnet capable of holding up to 72 lbs. (Like this neodymium disc magnet!), and a junkyard magnet able to hold around 7,000 lbs. Three credit cards were held to one of the magnets and then tested at a retailer to see if they were still functioning. Surprisingly, the only credit card that stopped working properly was the card exposed to the medium-strength magnet! Why Did That Happen? Drake consulted an expert for some insight into the experiment. A. Dean Sherry, a chemistry professor at the University of Texas at Dallas explained that the strength of the magnet’s field isn’t necessarily the determining factor. The important thing is the length of the exposure. Sherry explained that even the refrigerator magnet would have an impact on a credit card after a long enough time. This means that you shouldn’t underestimate a small magnet! Even the weakest magnets can deactivate your cards if exposed to them for long enough. While magnets are mostly innocuous household items, they pose a hidden danger. Keep this in mind the next time you’re using your Classic Horseshoe Magnet and avoid setting it near your wallet. We’re obviously huge magnet fans, but we know when they're not used appropriately. Keep your eyes on our News & How-Tos blog as well as our Magnet Safety page to learn more about our favorite thing (magnets) and how to use them safely!