The painting side of the car is about 150 ~ 300: 1. First, you can gently grind off the rust spots with very fine water sandpaper dipped in water, wipe them off completely, and apply a layer of primer to ensure that the rust will not expand and aggravate. If the new scratches can be wiped clean, you can apply the primer directly. General vehicles are equipped with a small can of original paint; Although this kind of treatment is not beautiful, it is not a big problem in a small place. You can also buy a touch-up pen in advance, polish it with water sandpaper after the primer is dry, and then color it with a touch-up pen; 3. Primer can prevent rust and increase the adhesion of topcoat. Don't be lazy and apply it directly to small scratches or inconspicuous parts with a complementary color pen. This method can be used to modify.