The above image is very flattering since most all the paint has come off, leaving the grey plastic exposed.
So I wet-sanded the non-chromed area until all remaining paint and oxidation was removed. I allowed the caps to dry for a couple hours. I then masked off the chrome face and the metal spring clips on the underside. I wiped down the surface to be painted with paint thinner to remove residual soap, sanding residue and finger oils. I rigged a yard stick as a holder for the caps and applied 4 coats of Rustoleum Black Bedliner with 20 minute dry times at 75 deg F between coats. I allowed caps to dry overnight before removing masking. I then allowed caps to bake in full sun during the day and inside at night for 36 hours. Then I reinstalled them!
The Bedliner from a rattlecan has a guarantee not to peel and should be more resistant to chips and scrapes. We'll see! I love the contrast and the texture