Question re: Restoring/Cleaning Black Rubber on Defrost and Fog Light Knobs

[Myami]

Hey Pelicans:

Hoping this is another easy one.

On my 84 Carrera, the rubber pull knobs on the rear defrost and front fog lights has grayed. Is there a product that will bring these back to black? If not, does anyone have the part number handy for the knob themselves? Assume I can unscrew them, swap over the logos and reinstall.

Thanks in advance!