When I originally did my factory wheels here is what I did myself:
Use Permatex Spray-on Gasket Remover (1 can per wheel) let sit for about 15 minutes. Scrub it with a brass detail brush for the small areas and then hose it off.
Once that's done you can do different things.
1. You could wet sand it all down with 600 grit sandpaper to remove any minor scartches then use Dulicolor's silver urethane wheel paint.
2. You can paint it clear or any other color you want.
3. You can wet sand it it down with 400 grit to remove any factory machining marks, then 600 grit, Then 1200 grit, Then polish the wheel with Mother's aluminum polish. This will look like a polished aluminum/chrome look. (almost mirror like)
You can clear coat the wheel which will slightly dull the mirror finish or you can leave them uncoated. The uncoated version requires you to keep them clean and waxed often to prevent corroding or pitting.
Personally I would do #3 and then claer coat them with Duplicolor's clear urethane wheel paint.