So I need to battle with dirt/oil and the bottom of my Alfa's. What's the best way to get the bottom as clean as possible? The cars haven't been driven in some time (last one 6 months ago) so the oil and dirt have dried a bit. I'm going to do one at a time. I have my jack stands and power washer ready, but what kind of chemicals best helps get all the crap off the bottom? Anyone have before and after pictures of their clean up?