Originally Posted by BrianM
Wet sanding 600 to 1000 to rubbing compound is fine as long as you are using a heavy cut compound like the 3M Super Duty on a wool pad. If you are using an orbital with the compound you may not be getting enough 'cut' from it.
My guess is you are not sanding out the 600 scratches completely. Make sure you sand in one direction with each grit say up and down with the 600 and side to side with the 1000 that way you can see when you have eliminated the scratches from the prior grit. Keep it really wet and rinse with clean water often.
Using that orbital with the compound I would run it at a little higher speed and you may need to make a few passes to remove all of the 1000 scratches. A circular is really the tool for this job with the compound. You are at lease using a WOOL pad aren't you?
Hitting it more with the Finesse It and wax will show the sanding marks even more. You have to get out the scratches completely from the previous process before moving on.
FWIW, regarding keeping the surface wet while wet sanding, I learned from a marine shop to put a little dish soap in a spray bottle, fill with water, and fine spray all along the way until each rinse. It works well.