Now I know why they make non-marking soles for boat shoes. What I don't know if how to clean the black marks my son's new shoes left on my deck (and cockpit and....). My deck has been painted, so I'm concerned about using solvents that I'm sure would take off the scuff marks, but might also take off the paint. An amazing variety of household cleaners didn't work very well. Any suggestions would be greatly appreciated. (Amazingly enough, the fact that my boat is covered with black scuff marks did nothing to spoil an abolsutely glorious day of sailing on the Chesapeake yesterday. And my son loves his new shoes.)