I have a titanium SurroundBar 42 and PSW10 that I will be putting up for sale. The grills have some small spots on them that I want to remove. The SB 42 had a small dark spot that I tried to sponge off with clean water. Doing this actually left a larger water mark and didn't remove the small mark. I should have left it alone. The sub also has a small (1/2") stain of unknown origin. How can I clean these? Should they be sent to the dry cleaners? Any suggestions will be appreciated.