2 days ago I noticed a burned plastic smell in my garage. At first I thought it was something in the garage itself, but when I smelled it again at a friend's house I knew it had to be coming from the altima. I checked under the hood, smell was not coming from there. So I checked under the car, where I saw the mess stuck to the exhaust pipe after the resonator, and before the muffler. I tried scraping it off with a knife last night, with little impact. Any ideas how I might get this crap off the pipe? Am I just going to have to deal with the smell till it melts away to nothing? It's mostly hardened now, so is there a chance it will catch fire?