I don’t think the chrome bits have any clear coat on them. I used chemical guys heavy metal polish and then a round of their V38 light polish to clean them up. It was a fairly easy job. They’re awkward to polish with a machine but it’s doable. Mine polished up pretty well. They’re not perfect, by any means, but a lot better than when what they looked like when I got them. My cross rails are color matched to my truck. I had a body shop do mine. But I’d assume because they’re metal you can sand them down and paint with any of the popular rattle cans that we all use here. I’m sure the coded paint from automotivetouchup.com will work. Maybe some of the other paint pros,
@05Single ,
@Fosscore ,
@Rocket Man can chime in with a suggestion for you on painting those cross rails?
Edit: the caps can definitely be painted with any of the rattle can paint that’s color coded to your paint code that everyone uses here!