As bad as it sounds, a lot of times I use gas. Carb cleaner works but will take off paint and all a lot of times, and it can get expensive for big projects, Wal-Mart has a real good on for $2 a can. I have used WD-40 in the gallon jug to get the heavy (petroleum cuts petroleum the fastest, not as fast as gas but WD-40 does work) and then wash with dawn or something like it. Scraping is sometimes necessary depending on how bad it is, I use a wood shive almost like a thin rook shingle or a big bondo spreader, they don't dig into the paint as bad as a metal scraper.
Careful your character's showing