[Nipper]

just starting up an old thread; I've been spending a bit of time under my car trying to get it spottless. The underbody is generally clean and can be washed with soap and water but there is an area around the center of the exhaust which has a black gunk caked on it. I'm not sure what it is, I'm guessing smoke/soot from the exhaust as when I bought the car the exhaust had a hole in it around this area. I had a lot of trouble getting it off and found that it was almost impossible to get off without a steam cleaner. Would it be safe to use a product like kerosene to get the gunk to thin out so it can be removed easiler, will this harm the undercoating, or should I just keep going over with the steam cleaner?