dirty

Here is a great trick to clean your fiberglass hulls with those nasty water stains

I just put in new rave valves after rebuilding the engine (piston locked up). The ski runs great, however after only 1 hour of running, the brand new shinny rave valves are really dirty/black! I cant imagine all this buildup, so fast, is good for them. Or is this normal? I am using Pennzoil...