if you want to clean built up crease and sludge off your engine, engine bay or to get tar off your underbody use oven cleaner no joke i just tried it after placing a lil bet that it wouldn't work as well as degreaser and well lets just say i lost my 20 bucks just apply it to the area leave it sit for the recomended time then wash it off with water and a rag though a word to the wise only use it to clean your engine bay if you intend to respray it i left it sit there a while and it discolourd the paint no worries though as its gettin sprayed.