[Fries-With-That]

If its been painted already, why not give the current paint a light sanding and paint it country cream or white.

You could also paint it white and using a feather drag lines of black paint across it to give it a marble appearance.
Drag the black paint across the white when the white is still wet it blends the black into the white and you get a grey/black/white marble effect.

Rework the same area while the paint is still damp to create the veining with feathers. Use Goose or Swan feathers for best results. (crow feathers will do too)
Lightly hold the feather by the quill and pull it diagonally across the surface, turning it from side to side. The secret to believable veining is to have subtlety.