DuPont 3812 enamel reducer is all I've used for most of 40yrs. No residue at all and won't harm the paint.
Gonna do the Dawn thing and I picked up some Prep-All to get the stubborn stuff. Will advise on the outcome. Once again. Thank you everyone for your input.
I've been using simple Green , water and my old cordless tooth brush the rotary kind...lost of old hardened compound and cuttting stuff left on the car that sat for a few years. It seems to be working and couple more times and she will be looking fine.