Rusty chrome rims

I spent the day trying to restore some old rusty chrome rims on a 2001 Buick Lasabre for a friend. A lot of the rust seems to be on the surface but there are a few areas that seem to far gone. Only thing that's working is rubbing the crap out of them with Meguiars Ultimate Compound. My fingers hurt!!!! After many hours I've got two of them looking pretty good. Is this surface rust from little pits in the chrome? Am I doing it the best way?????

I'm actually surprised to find chrome under this surface rust.

Well, I just finished the last two this morning using the, very difficult, Utimate compound method. They turned out pretty good and I sealed them with DG 111/601. I was gonna try the 0000 steel wool method but I remember years ago it dulled my 77 Thunderbird bumpers. I'm guessing that the rust will return eventually without constant maintenance. I kinda miss the old chrome steel rim days!!!!! Had me a sweet set of Cragars on that old T-Bird!!!!