I think you have to replace these pieces. I believe the chrome has worn of the plastic. You can't polish it, nothing you do will help. I have this on my grill and its worn chrome.

these pieces arent the plastic ones.. these are the metal ones around the car

I went crazy with this a while back on my 1988 560SL. I found out that the metal trim on the 560SL is not chrome it is anodized aluminum. Therefore chrome polish did not do anything, nor did aluminum polish. I did machine polish some of the pieces that I removed with a bench polisher and rouge. This had reasonable results, but the operation was very dangerous. Some of the parts did fly away and hit the wall with gerat force. Also I belive the bumpers are covered with stainless steel.

I guess the thing I need to look for is an anodised al polish and a stainless steel polish. Any one hear of such.

John Roncallo

bing mothers magnesium/aluminum polish its for wheels but just becaus it isnt on the wheel does make it different i think

http://www.mothers.com/products/productcatalog/wheelprod.html

im going to find some soon and try it out