Been doing work / cleanup on my 05 crf250x carb. Took a quick look at my intake valves and there is quite some build up on the top of valves. Could be gas vapor deposits or oil deposits. My plan is to remove the entire head and rebuild. Or purchase a new 07 CRF250R Head with Kibblewhite Valve & Spring Kit. MY QUESTION TO ALL IS: Since I will have the head assembly off what are your recommendations with inspecting and cleaning the piston???? Thanks for your input and advice.