I stopped by a detail shop. He said there is no easy way to get it real clean.
They would have to use a degreasing type of soap and rub it in good then use the extractor. Our shop would want 1.5 hours to detail it a $125.
He then continued to say since the metal hood & surrounding area is also dirty you might as well just do it at home with soap on a brush etc...or at power wash bay and blast the F out of it. LOL...
Ya.. now I am not sure if I should do it now or just ignore for a while longer..
and clean it in the spring, after a wet nasty winter may be best..