Does anyone have a way to clean the passages in the cylider heads? When I did the UIM/LIM cleaning that was the only part I wasn't completely thorough with cleaning. Mine hade a lot of build up in them as did the valve stems from what I could see. I vaccumed out what I could but I did not want to risk getting this gunk lodged in the valve seats. Should I worry about that or just clean away with B-12 and vaccum. Any experiences/suggestions?