hHow clean is clean? I have scraped it with a a scraper, wire brushed the residue left sticking to the joint. There is still a thin layer of sticky black residue left from the wire brushing on parts....
I am restoring or mostly rebuilding a late 1980's Holiday rambler. The old tape was coming loose and had some very big bubbles in it. There has been water intrusion in the area of the old tape. I figured I should fix the many Visual problems on the roof. Before removing the interior celling products, to redo the bedroom and cabinet damage. This is what it looks like after cleaning with the metal prep solution and the degreaser. part a