When corrosion occurs on the metal of your vehicle, rust will begin to form. It will appear as an orange or brown color on the metal’s surface. When rust begins to form under the paint, it will appear as bubbles on the surface. These bubbles, if left alone, will slowly begin to eat away at the metal until there is a hole. You can fix this problem by removing the rust bubble on the metal.
Use the putty knife or metal scraper to scrape off the paint that has bubbled up from the rust. This will expose a small area of rust and remove any loose paint.
Rub the sandpaper over the rust area in a circular motion. Repeat this process until you have removed the layer of rust, or have reached bare metal.