For minor scratches or rust that have already appeared on the vehicle body, if left untreated, they can easily rust further—but they may not be worth paying for a trip to an auto detailing shop. In that case, car owners can handle the issue themselves using some simple methods.
    Touch-up paint pens can handle small scratches: If the rust isn’t too severe, you can start by gently rubbing the rust spots with an extremely fine wet sandpaper dipped in water, but be sure not to rub aimlessly—sand in the same direction along straight lines. Once completely cleaned, apply a layer of primer. For new scratches, you can clean the area and directly apply the primer. Afterward, if your vehicle comes with a small can of factory paint, you can wait for the primer to dry, then smooth it out with wet sandpaper, and apply the factory paint over the primer. If no factory paint is available, you can buy a touch-up paint pen and use it to color the area. While this treatment may not be as effective as going to a detailing shop, for small or inconspicuous scratches, it can help prevent the rust from spreading or worsening.
    Applying toothpaste can provide temporary rust prevention: Another option is to use regular toothpaste. When you notice a new small scratch, gently apply the toothpaste in a circular motion to the scratched area. Don’t forget to reapply it after rain or washing the car. This method can generally reduce the visibility of scratches and also serve as a simple barrier to prevent rusting—at least for the short term. It works especially well on white paint.