Lucky for me this wasn't the first time this had ever happened to me. My last bike was an 85 Honda Davidson as some call it. Its a Honda Shadow VT1100C and since it looks quit a bit like a Harley it got its nickname. I had laid the bike down and since the insurance was to pay for it, I decided to change out the stock exhaust for the only exhaust available for it, by a company called MAC that I've never heard of. No heat shields of course....would recommend them at all. However because of the way that the pipes had to run it was right by the right foot peg. Very close. And often I was melt some of my boot onto the pipe.
I pretty much figured I was screwed, but was still quite happy that my exhaust was loud. One day a buddy came over and noticed the spot. He told me he could take it pretty quickly. He pulled out some Blue Magic brand metal polish cream.
I told him he was crazy and that the leather was cooked into the pipe and had been that way for months. He ignored me, grabbed a microfiber rag, dabbed a little on and kept rubbing away at it. Finally the spot was gone...and I was forever sold on it.
Today was quite the similar situation, only I knew I could get it out. Don't get me wrong, its not really quick, but I think this only took me about 30 minutes. You have to put a little elbow grease into it and push while rubbing it in. In fact I use my nail thru the microfiber towel. Look its magic! It has ammonia in it, so you'll want to be careful. Note: DO try this at home, this was not an actually professional.