Score the balls lightly with a soft lead pencil. I use a 2B. Roll the pencil marks in with a finger tip. Some people say avoid putting the reels in wash aid but I do this then throw the reels into a bucket of hot water straight after pulling off the film. Then clean reels and balls with a tooth brush after hanging all the film and leave to air dry. If all else fails throw the reel in the bin! I did this last weekend with a particularly bothersome reel which has evaded all attempts at restitution. It wasn't a genuine Paterson - one of the cheaper imitations.