lemon juice didn't work? Rubbing alcohol didn't? bleach just ate up your jeans? randomchemX just destroyed the surface of the ball?
Clean & Clear Continuous Control Acne Cleanser, which has 10% of the active ingredient Benzoyl Peroxide (that's the important part, other acne cleansers have the acid that is used for wart removal...) has -entirely- removed a vicious stain from my white Sil-X!
I don't know of the affect it would have on a colored ball... buuuuut, here's the process:
apply thick goopiness to stain, set next to a lightbulb (about an inch away) and let it sit for several hours. Remove ball and wash off goopiness. Stain will be reduced and/or gone. If reduced, repeat!
I'm really excited about this, I'm going to use it on a juggling ball I left sitting on a receipt as well.
--Taken from a post in the forum.