Just the right amount of black spray paint will do the trick..... only cheaper!
Be sure the plastic is VERY clean.... use a wax and grease remover/paint prep solvent....
I use DX330 Acryli-clean (available at local parts stores-Napa, Auto Tire & Parts, etc)
Just mist the paint on very very lightly from a good distance.... use flat or gloss black (flat might match the colour of the surrounding area better)....
Wetsand between coats with 1500 grit.
After paint dries for a few hours use some wax to protect it.....
I've done this with many things.....
