This is what I did for a 95% factory look without touching the painted (charcoal) portions. The reason I say 95% is because I did not tape off or protect the painted portions at all during the sanding or clear coat phases. any minor scuffs I made to the painted portions were easily covered with the overspray from the clear coat.
1. Might as well give the wheels a good cleaning with soap/water and degreaser for the harder stuff.
2. Use 300/400 grit to remove the failing clear coat and oxidized aluminum. Now is also the time to level out any curb damage that has occurred around the rim.
3. Worked my way up to 800 grit so the metal had enough roughness for the clear coat to stick.
4. Used mothers aluminum polish on a drill attachment to make it shiny.
5. Cleaned the wheels with soap and water and then dry thoroughly.
6. Taped off the tires and shot 3 layers of clear following the directions on the can.
I didn't bother going back and wet sanding because wheels typically get beat to hell and any clear coat I could leave on there would be slightly more protection.