I'm getting ready to do a full detail on my new Blizzard Pearl Prius. I will be claying the car, followed by a DA polishing (PC7424) using Duragloss 501 the Duragloss 105. A final coat of Duragloss Aquawax will then be applied. My question is can i use the above process on the black spoiler and grills? I'm not sure if it is paint or plastic and whether the clay/polish will do more harm than good.