One way to tell if they are still clear coated is when you use a metal polish on them, the polish will turn black almost instanly on the cloth and on the wheel if the clear coat is gone.
If not, then the clear coat is still there.
Then you need to treat them as if you were polishing paint.
A medium cut rubbing compound followed by swirl mark remover then wax.
If they are down to the bare aluminum, then you need to make sure that all areas are bare of clear coat. Clear coat can be removed by using nail polish remover (acetone) on a cloth, letting it soak, then reapply until the clear coat flakes off.
Then you can start to bring the finish back on the wheels.
Step 1:
Wetsand with 1000 grit wetordry sandpaper. You can go down to 400 grit for stubborn spots, then re-sand with 1000 grit.
Step2:
Polish with Nevrdull, Mothers, Hapish, Semichrome, POL, Wizards, or whatever aluminum polish ( I like Wixards because it smells like bubble gum) unti bright and shiny. A good buffing ball and electric drill makes it easier. You can get them at paint finishing stores.
Step 3:
Wash with GOOP hand cleaner followed by Dawn and water to get the residual polish off the wheel.
Step 4:
Repaint the black parts inside the wheel spokes.
Step 5:
Wax or re-clearcoat the shiny part of the wheel.
Personally, I like to leave the aluminum bare so it can be re-polished once a year.