The driver’s side front wheelwell had a small amount of rust, so I took off the rubber inner guard, sanded down the affected area, then painted on some rust converter. This chemically changes the rust patches and neutralizes its ability to spread. It also hardens and strengthens the painted areas. After it cured (about 20 hours) I painted on some primer as shown in the picture below. Since this is mostly covered up by the rubber guard piece I didn’t bother painting it, although on second thought I probably need to do so, to ensure nothing gets through the primer.
