I like how husqvarna caps are designed to lift out dirt when opened.
Anyway, carbon buildup seems unavoidable with how impure our gas is, and the extreme heat chainsaw engines operate at. Looking into the benefits of polished pistons, there seems to be no clear answer as to if it is better or not. I think one study said yes, but some race car builders seem to think they lost a smidge of power until the polished pistons got a layer of carbon on them. The only way I have found to prevent deposits in a chainsaw engine is not to let it get hot, and use a heavy mineral oil like Echo Red Armor, or castor oil. Castor will definitely bake on and turn to carbon, but in cooler conditions it forms a barrier keeping carbon from sticking.