wax rear bumper on XLS?

To those of you who have a XLS, do you polish/wax the rear bumper? The rear bumper is painted a dull grey. I think I waxed it last Fall, but It was some wax that easily came off. I put a fresh coat of Zymol on last night, but I skipped the rear bumper. The bumper is a matt -- rather than glossy finish.

 

[spiper]

If its flat waxing it wont really make any difference other than protect the finish somewhat. I dont see why you couldnt though. I really dunno Korey, my bumpers are chrome.