Do you own a variable speed buffer
if so buy a lambs wool buffing wheel and apply some Jiff to wheel then slightly wet the wheel in some water - set to slow speed and buff away until wheel is dry ... repeat above
Note *** when wool dries out, ( Lack of water/ jiff ) it will polish the plastic to a certain stage ... if speed is too high it will burn the plastic.
Repeat above jiff/ water process and burn mark will be removed.
Hope this is of some help.