What are some sources of damage to an ATM card?

I stayed at a hotel once for a few weeks. Every few days my room card would quit working. After the third time, I spoke to the desk clerk about it. He asked me where I kept my room card when I was not holding it. That's when it dawned on me. I was putting the stuff from my pockets on top of the TV. The TV had a cathode ray tube (CRT) picture screeen (not like today's LCD or plasma). The tube emits electromatic waves. By putting the room card on top of the TV, the magnetic strip on the card was being slowly erased by the TV's magnetism. Once I stopped putting my card on the TV, I never had the problem again. There are other areas to be concerned about. If you work in a factory that has high electric current equipment, there could be strong electromagnetic fields that can earse the magnetic strip on your card. The longer the card is in this type of arae, the more likely it can be a problem.