I agree with rjsjea. I personally have used rust mort on chassis components, and on floors. But for visible painted bodywork, I won't trust anything other than shiny silver clean metal. I have the roof of my '73 Beetle as evidence. As I understand it, when sheetmetal pits, you are not seeing the full depth of the damage. The cavity is wider underneath the surface. See http://www.sandvik.com/sandvik/0140.../HandbookWeb/00CB4E68B7653027C1256761002178E3 I don't see how you can really know if a chemical is doing it's job in that instance.