My daughter went through 2 casts before we found this waterproof castliner material on the internet. She got the first two wet (broke wrist at beginning of summer and tried playing around the pool and at the beach with all sorts of contraptions to try to keep the cast dry ... nothing worked 100%). My ortho suggested this castliner, I bought it and it was delivered to my home in 2 days ... went to ortho the next day and she was cast into her 3rd cast with the waterproof material and we were all so happy. We only wished we had found it sooner! She was swimming in the pool, bathing, no stink, no itching and when the cast was removed ... her arm & skin looked great! Here is the link ...
P.S. My ortho only recommends it for short arm casts b/c the water can drain out easier.