This is a quote from the Sidewinder website:
WARNING #3 DO NOT USE GASOLINE, LACQUER THINNER OR ANY STRONG SOLVENTS TO CLEAN O-RING CHAIN. IT WILL ATTACK THE RUBBER O-RINGS. USE HOT SOAPY WATER AND A NYLON BRUSH. A WIRE BRUSH IS A NO-NO!!
I agree with this, o-rings need careful attention if you want the chain to last. I use Sidewinder's P-51 lube because it doesn't require anything more than soapy hot water to brush off. Some others I've tried are much more stubborn to get off. The Sidewinder stuff is a bit expensive, but I feel it's totally worth it, it's great stuff.
Be careful reading some suggestions for chain care, as dirt bikers don't always use o-ring chains and street bikers don't have the same dirt element to deal with that we do.
-RR