salty,
You do not want to put wax on a model you are going to paint. If you want to polish out scratches use Novus plastic polish. There are 3 grades of polish, Novus #1, #2, and # 3. Each is a little finer, or coarser, depending on how you look at it. I find that Novus #2, the middle grade, works fine for preparing aircraft surfaces for a natural metal finish.
I prepare the surface by sanding the entire surface with either 600 or 800 grit wet/dry sandpaper. I wet sand. If I start with 600 grit, I go over that with 800 grit to make it easier to polish the surface.
On a kit with raised panel lines this is not very practical unless you sand off the lines and scribe them. If I do not want to do that I just polish the kit with a heavier grit Novus, and then do the finish polishing with #2. Hope this helps.