[rohrmann]

When using EternaBond tape to repair rubber roofs, they recommend their own solvent or acetone to clean the roof prior to applying their tape. I have used acetone on the roof material, and it doesn't seem to hurt the rubber material. Of course, I don't leave it on real long, but it does remove the sticky stuff. After removing the old butyl material around the window frames, the acetone worked like a charm, so I know it will clean the butyl material off. Good luck.