Thanks for posting this question, I'm interested in the answers, too. My bikes are currently in a basement room with unpainted drywall, but at some point I may want to paint the walls and I might need to remove some tire marks, chain lube stains, and the like. I'm not sure that a light color paint will cover tire marks, so I'd like to at least lighten them up before painting. Mr. Clean Magic Eraser (R)? sounds like it might be ideal for this, though sandpaper might work just as well, I'll try that first since I have it lying around.