I have what looks like from reading the forums, I'm guessing here, my wife's tennis shoe that appears to have scorched on my right side exhaust. It's white in color and very thin. I have tried never dull, pledge, windex and the pipe shines like new, but that mark is still there. I asked the dealer about it and he told me to bring it to him and they would use a solvent that "cleans anything" off of pipes. Would not tell what this miracle solvent is. What would you astute gentlemen recommend to this here rookie to get this stuff off my pipe. Thanks in advance.