[SeaSlugs]

stop using gas for one, kerosine is just as effective and not likely to explode if it finds a stray spark... what i do with caked on stuff is let it soak in kerosine and scrape away with a putty knife, usually i can work it off in big chunks (scrape behind it to "peel" it off) for the little bits a stiff brush and some acetone does wonders. Once its like 98% clean i take it to have sandblasted to get a nice 100% clean surface to paint on. (wipe with acetone to remove remaining oils/dust off before paint)