my ex-husband, when he rented the back room, drew a rather large mural on the wall in pencil. I got the super professional cleaner and that took off a layer. Then I used comet and a toothbrush and a few new muscles later have gotten most of it off. However, there's still just a HINT of it on the wall. I really don't want to paint that room. Any other ideas? I did the Comet twice. First I let it sit 1 minute and scrubbed. Then when that didn't get it all off, I made a pretty thick paste and really gobbed it on there and scrubbed hard and left it for a while. then came back and scrubbed it again. Think 3rd times a charm or should I try something else. This was THICK DARK pencil marks.