Question : Why would the magnetic strip on a credit card scan; if wrapped in plastic wrap, when it originally wouldn’t.
I work at a hotel, and our room charge/key cards often don’t scan on the first couple of tries. If we wrap them in plastic wrap, or thermal paper from the receipt printer; most of the time they will then scan successfully. We are scanning them when a guest is making a purchase at a computer/register. We hardly ever have this problem with regular credit cards, just the hotel’s cards. Just wondering what is the science involved. Thanks
plastic card printer

Best answer:

Answer by DigitalBlade
The magnetic strip on the card is very sensitive to magnets. That’s why the reader is tuned very low to avoid damaging the strip. If there’s any dirt on it, it won’t scan. When you put the paper/plastic, you clean up the magnetic head. Remember tape players? You get the best sound when the head is clean.