"wet sanding" or "color sanding."
What do these terms mean and when and how should you use these procedures?
Sometimes the only way to remove or lighten a heavy imperfection is by sanding the paint surface. This can be a fast and effective way to remove a heavy scratch or scuff, if you are skilled and very careful. On the other hand, this method may lead to a trip to the spray booth if you are over zealous and not aware of when to stop.

During the process of wet sanding you are actually "shaving" a minute layer of clear coat off the paint surface to level out a deep scratch. This is also the process used to remove scuffs or marks left by other cars. Wet sanding is also used in many body shop procedures such as evening out a run or sag, eliminating dry spray, "knocking down" too much orange peel, or getting rid of dirt that got caught on the finish during the paint process. In many cases wet sanding can be more effective than trying to compound these imperfections out. Wet sanding will not create the heat that compounding will, but many times is more aggressive, and special care must be taken throughout the entire process.