Discolored/ stained plastic

[BLyons]

While helping my neighbor wash his car i noticed that the plastic under the windshield has a discoloration. It is multicolored and almost looks like oil staining. The most noticeable colors are blue and yellow. Any idea what caused this, or any suggestions on how to remove and prevent this?

[DaGonz]

There is a product called Forever Black, It comes with a precleaner and the actual product itself. It comes in a squeeze bottle and has an applicator tip like the kind that comes with liquid shoe polish. You may need to do a few coats to get a uniform look, but it does work. I used it on the faded trim on a Toyota Sienna minivan's rear bumper molding and it looked like it did when it was brand new.