Eli5: When your credit card doesn’t read at a credit card machine, why does covering it with a plastic bag suddenly make it work?

Question

Had this done multiple time at the register. Card not reading, so the cashier will cover the ribbon or the chip with a plastic bag and YATZEE, it goes through. Why?

In: 407

Answer 1

Sometimes it’s the card, as described in the other response. Sometimes it’s the reader itself. When it’s the reader itself, it could be due to having been used hundreds if thousands of times, which not only slowly deteriorates the magnetic reader, but also changes the physical distance between the cards and the reader so that the information isn’t exchanged properly. Next time it happens, try bending the part of the card that isn’t stuck in the machine either up or down (depends on the machine and card). Should be just as effective as the plastic bag trick