In general, you’ll want to start wet sanding around 600–1200 grit, and follow the same dry sanding rules for working up through the grits, jumping up 200–500 grit between passes (depending on how meticulous you want to be).
One may also ask, what can I use for wet sanding?
Wet sanding is a process where we use special sandpaper that is supposed to be wet with water. Very wet. The water acts like a lubricant plus helps remove tiny particles so that the sandpaper does not get clogged and create deep scratches.
Thereof, what do you use for wet sanding a car? Wet sanding requires a lubricant to prevent the sandpaper from burning the paint. Fill a regular bucket with water and a small amount of automotive soap. Do not use an automotive soap that also serves as a wax or a polish. You may also use dish soap for this application.