Guy at a gas station 20 years ago showed me if you swipe a credit card through a platic shopping bag, it will go through the first time.
Hold the credit card tight so there are no creases in the bag.
Not sure why that works.
This works because the head is dirty. The plastic allows the strip to once again move over the head at a constant distance. Smoothing the data and lowering error count. See my comment on cleaning it with a dollar bill.
(post is archived)