I shot the Obon Dori Festival yesterday using a "clean" CF card. How do I know it was clean? Well, my wife ran my jeans through the washing machine with the CF card in a pocket. No problem with the CF card, I think that these darn things are pretty well indestructible. However, I rescued the card before my wife placed the jeans in the dryer
I did give the card a couple of days to dry out before I placed it in my camera.