My piston ring grooves had quite a bit of (oily?) gunk settlement. Is it appropriate to clean them with a dental pick? Is there risk to scratching them? My assumption is not since it is not a gasket mating surface. Also, what chemical is best to clean it with, WD-40, brake cleaner or something like acetone, mineral spirits or alcohol?
Also -- should I lube the grooves (with regular engine oil or assembly lube) when installing the rings (to facilitate moving to the right position)?