Melted plastic on a muffler can be a highly difficult substance to remove. The fumes given off by the burning plastic each time you run your car will motivate you to attempt to remove it. There are two different times to remove the plastic: when the muffler is hot and the plastic is slightly melted, or when the muffler is cold and the plastic is more solid. A combination of both will be needed to remove the plastic completely.
Wait for the plastic to cool. You will need to wait around an hour after switching the engine off before it is cool enough. Be sure to wear gloves if you are unsure as to the temperature.
Chip as much of the melted plastic off using the paint chipper. This will be laborious and time-consuming, but will remove most of the melted plastic. Try and minimize chipping the muffler itself.
Dip the cloth in the white spirit and begin to rub at the remaining areas of melted plastic. The white spirit will begin to corrode the plastic, which will help to loosen it off. Wipe excess white spirit away using another cloth.
Turn the engine on and allow the muffler to get hot. Once it is hot, turn the engine off, and allow to cool. Repeat the process until all of the plastic has been removed. Do not attempt to work on the muffler while it is hot.
