Life In 19x19

I recently bought this portable Go set: ( http://www.amazon.com/WE-Games-Ultimate-Full-Size-Silicone/dp/B007P3L64E/ref=pd_sim_sbs_t_3 ). It's actually a fairly decent set. The only gripe I have with it is every time my stones of opposite colors come into contact with each other, I start getting black marks all over my white stones. The marks come off with some warm water and elbow grease, but it's still really annoying. could there be some kinda residue on the stones (from when they were made) or something of the like that could be causing this? (btw when this started happening, I scrubbed the black stones down with some warm soapy water, and it made no difference.) Any ideas on how to stop this, or am I just doomed to be continually cleaning my white stones?

Linokai wrote:ny ideas on how to stop this, or am I just doomed to be continually cleaning my white stones?

Put the black stones in the washing machine and hope that all the black stuff gets off.

You must determine what's causing the black to transfer. Is it rubbing off? Is it a stain? Are the black stones made of softer plastic? Easiest solution is to obtain a set of ultracheap glass stones.