Paint chips and minor scratches can be repainted using a toothpick for a brush. First, use a typewriter eraser to clean away the rust from the damaged spot. Then, using either touch-up paint or leftover paint from a past body repair (always ask the body shop to give you any leftover paint after having work done), fill in the scratch with several coats applied a drop at a time from the end of a toothpick. The results will not be cosmetically perfect, but the rust will be prevented from spreading under the paint and further damaging the body.
By joesgirl