| HN Mirror

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-fi...

[2] http://www.popsci.com/article/2007-11/cure-failed-credit-car...