Whatever you do, DO NOT use Scotchbright (those little green scrubby pads)!
I'd just gotten to work and was putting my cover on when a co-worker came over to "help". I started to tell him I was just pulling it over the windshield and handlebars as the motor and pipes needed to cool a bit first, however, before I finished my sentence, he pulled the back down right onto the pipes. Even though I immediately pulled it off the pipes, there was still some material that had melted right to the pipe. He felt really bad, but I told him it was no problem...honest mistake.
Got home that evening (commute allowed the stuff to bake on for at least 30 minutes) and was armed with gasoline, goof-off, bug/tar remover and oven cleaner. The bug/tar remover did nothing. The goof-off and a rag removed "some" of the stuff, but not much...then it just stopped working...almost like the residue had developed an impervious shell. Gasoline and a rag didn't fair much better. I protected the bike from overspray and warmed her up before spraying the oven cleaner. I let it sit for a while then wiped it off. This took care of about 75% of the goo. However, some sections were really burned/baked on. I repeated the process, but this time I used a Scotchbrite pad in hopes of having the oven cleaner penetrate better. Upon wiping off the oven cleaner, I noticed with horror that my pipes were now dull. I thought maybe I had used too much oven cleaner. But upon closer inspection, I could see all the tiny scratch marks left by the Scotchbrite had dulled the finish. I ended up leaving the remaining goo on as it wasn't as noticeable as a dulled surface.
DON'T USE SCOTCHBRITE...OR ANY OTHER ROUGH SURFACED MATERIAL!