They'll wrap your card in it and swipe again. It's supposed to counteract a weak strip (or weak reader?), but I'm not sold on the technical explanation[1]. Popu

They'll wrap your card in it and swipe again. It's supposed to counteract a weak strip (or weak reader?), but I'm not sold on the technical explanation[1]. Popular Science has a more vague explanation, that I also don't follow[2]. [1] http://mentalfloss.com/article/50199/how-does-plastic-bag-fix-buggy-credit-card http://mentalfloss.com/article/50199/how-does-plastic-bag-fi... [2] http://www.popsci.com/article/2007-11/cure-failed-credit-card-swipe-it%E2%80%99s-bag http://www.popsci.com/article/2007-11/cure-failed-credit-car...