I've seen a video where it didn't appear WD-40 damaged the O-rings, BUT, any light penetrating oil and even kerosene will certainly cut excess grease/oil/lube. The problem is, it does exactly that, and also washes the chain lube and grease in the o-rings away. I used kerosene on my chain once in the mid-'80's on my GS1100ES, and it destroyed my chain in short order. Never again. Me, I use PJ1 Blue Label, and I just spray a lot on the chain and use it to wash off grime, because when the solvents in that (or any other chain lube) evaporate, it leaves nothing but chain lube behind, and you know that the volatiles are specifically made to not degrade the lube or the o-rings and their grease. I'll also spray a rag heavily with the lube, and use that to wipe grime and excess lube off after I lube it really well. Works great and I don't need 2 different chemicals, AND it leaves the proper lube behind and nothing else. I've got over 20,000 miles on my chain now, and typically get 20k-25k miles on chains and sprockets. With this set in particular, I've been lubing/cleaning the chain every 400-500 miles and the set looks awesome, plenty of wear left. I'd REALLY like to see a belt drive that could handle the hp/tq of modern sportbikes so that this becomes a moot point. Ah well...