Alas, I got the dark rings on the cylinder face, BUT they were removed quite easily - and the bore was clean even before I started tio clean it. I think the extra amount of lube really aided in this effort. I have just gone to the metal dealer (Scrap yard) and am putting in a bit for a few more hundred pounds of lead (we get a lot of old lead water pipe from tear downs in the area). Usually, Unique blackens just about everything - not this time...save the cylibnder face, of course. :-)