How to Fix a Stubborn Credit Card

April 13, 2012 at 2:00 am 5 comments

By Chad Upton | Editor

Have you ever worn out a magnetic card? You can ask your bank for a new one but it usually takes a few days. In the meantime, you can put a piece of clear tape or use some receipt paper from the cashier to cover the magnetic stripe while the card is swiped.

Usually, the cashier will do this for you, but if not then you can ask them to try it. Some may even use a plastic bag, but any thin barrier may work. Be sure it’s very thin so it doesn’t get jammed in the card reader.

Many people know about this little trick; the real secret is why it works…

As a magnetic card gets used, the magnetically charged particles get smeared. This smearing repeated many times creates  magnetic noise which distorts the data when read. The magnetic strength of the noise is low enough that a small barrier can block or reduce it enough to get a proper reading from the card.

For a bit of anecdotal evidence, I worked retail back in college and I used this trick hundreds of times — it worked nearly every time.

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Sources:, wired magazine (Nov 2011)

Entry filed under: Demystified, Money. Tags: , , , , , , .

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5 Comments Add your own

  • 1. Bekah  |  April 13, 2012 at 8:32 am

    I worked at a gas station and did this every day for customers, but I’d put a plastic bag around the card. Worked every time! I didn’t know HOW it worked, I just knew that it worked.

    • 2. arsenal1again  |  October 21, 2014 at 8:30 am

      You encountered people “Every Day” with worn out magnetic strips?

      This is very thin …. in fact it’s way out there.

  • 3. Fadi El-Eter  |  April 18, 2012 at 8:10 pm

    Thankfully, new cards have this SIM like thing and they don’t need to be swiped anymore. (the downside of this is that we have to enter our PIN)

    I never knew about this trick though – honestly I sometimes look at my card and think, what if it’s worn out at one point? What will I do? Thanks again for the tip!

    • 4. Chad Upton  |  April 19, 2012 at 12:11 am

      Although chip/smart cards are pretty popular in Canada and Europe, they’re pretty rare in the US… swiping is still the standard here.

  • 5. Charm  |  August 18, 2012 at 12:35 am

    I always put a clear tape on the magnetic strip on any new cards to prevent it from wearing out in the first place. But really glad to know the exact mechanism of why worn out cards don’t read well! Thanks :)


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