The 'chrome' surrounds on the windows of my Porsche Macan S have taken on a white, milky look and I cannot get the trim clean. Not knowing if the trim is chrome, aluminium or even plastic look-alike I have tried non-abrasive cleaning materials like car polish and a mild all-purpose cleaner but none make even the slightest improvement. I thought that one of them would have brought up the bright finish. What should I use to restore the finish?