I just did door panels for my 74 RR clean and scrubbed about 4 times then wipe clean with lacquer thinner, sprayed with rattle can adherer, sprayed with rattle can primer for plastic, then with my sparyed gun painted them with dupont interior paint, mixed at local parts store, all the products I purchase from the paint or auto store were for doing plastic panels, paint was about $46 bucks a pint,not cheap but they look like new, and you would never know they were ever black panels, I painted them white, and will probably do the rest of the interior trim the same way. one happy camper here, main thing is cleaning them,take your time and do it right.