I have a 55 Plymouth belvidere, what's the best way to clean off the white powdery paint residue and shine up the original paint (too good patina to damage, I'm trying to keep this as original as possible)
Does it have a clear coat?? Because if it does, that "white powdery" is the clear coat breaking down and the only fix is a repaint. If there's no clear coat, get the Turtle Wax PASTE rubbing compound (don't use the liquid one). It's best to rub it out by hand, but if you use a machine, don't press down hard and keep away from the edges.
Wash it with car wash soap, then buff it out....some of the paint will probably go away when you do this. And it will look kind of odd, but that is what's trendy today. I had a car with a nice powdery white paint job, and I just left it alone, I never washed it during the 6 months I owned it. And it ended up in a magazine
As I have said before many times - wipe down clean car with Penitrol, and wipe off. Easy peasy. Done it with numerous cars and boats. You will not believe the results !
A used car dealers trick. Use Comet or other scouring powder a sponge and lots of water. You can do the whole car in half an hour. Wash it a second time with very soapy water. I have done hundreds of cars like that. I sold a lot of cars from the late 60's -70's when I was a used car dealer in the 80's. No clear coats and lots of dead paint.
Here's a members 61 Parkwood wagon before and after CLR. A quick coat of clear over the finished product.