69 RAM AIR lV judge build sheet HOW CAN I CLEAN IT

[HEMIBEE]

just wondering if anybody has tried to remove the rust and dirt from a buils sheet, i pulled the tank out of this judge today to prepare for a repaint, i also wanted to get some input on how far i should take this repaint,i didnt want to paint it but the original paint had bean spot repaired in a few areas and the bumper is faded and i want the car to look better, the body on this car is great but it sat for a long time and the frame is covered with surface scale and some spots on the floors are the same way, i wanted to leave the car as original as possable, the jams and trunk area all look great and the interior is mint, what are your thoughts just painting the ouside body and not takeing the car all of the way down to make the bottom look as we all want it to look?? sometimes you just dont know where to stop.