They will strip wax. Use them before you start polishing and afterwards all you need is soap and water to keep them clean.
Yeah it works. I have both and I wash mine after each use. I use them to polish out my wheels that are painted.
This should give you an idea of the results. I have both a mini power ball for the face and a cone for between the spokes. I used a compound on the ball and cone and polished by hand as the power ball was not dry by the time I needed it for polishing.
Before (don't mind the ding in the wheel)
After