I tried Marykate Inflatable Boat Cleaner on the rubrail grunge, to compare it to acetone, etc. It's just about as good. This stuff seems to be esentially WhiteWall tire cleaner in another package, though. I think I'll continue to use it for a while, as it takes much less effort, and doesn't evaporate quickly. As acetone evaporates, it redeposits the residue that you haven't been fast enough to wipe off back onto and into the rubber rubrail. The only concern here is that, like other strong cleaners, as it dribbles down the side of the boat, I'm sure it's stealing some of the wax I worked so hard to apply! Acetone evaporates before it can run down. World's full of tradeoffs, though!