I have a non-magnetic(aka card with chip) credit card. I had the classic accident where it took a quick bath in the washing machine. :) Some questions came in mind immediately: - Are they water proof? - Lets say I try it and works. What are the chances that it will break eg 4-5 weeks later due to the wash?
Up to some point they are. Under the metal pads there is usually fiber glass, then the chip and everything is covered by a glue. Then embossed on the plastic card. I would say that even if the water touches the silicon there is no problem at all. The only risk I can see is the metal contacts becoming rusty, but for a short contact with water that should not be a problem. Another thing is the possibility of breaking it through mechanical shock in the washing machine. Cards are designed to stand some flexion and other mechanical stresses as many people just carry them in their jeans back pocket and sit down and nothing happens. I would say if after the "session" the card still works, no mechanical damage has happened and won't happen.
Those cards are like phone sim cards or "smart cards" used by laundry machines or Fedex/kinkos printing kiosks. They are glorified eeproms with no internal battery. They will not break from contact with water, or from the simple agitation of a washer machine. The worst case scenario is extended time in hot water or the dryer, will cause the credit card plastic to separate. Unless you make a habit of it, you won't have an issue.