This what I used from wilko 7.50 for a spray and was not described to do plastics on the web site but from looking on rustolium main site said plastics as well so took a punt
ive just cleaned my headlights on the Honda Jazz they were a nice shade of brown , when the car is cleaned the lights remain brown so I got the WD40 out and tryed it and they come up lovely it cut through the brown crudd easily and they look as good as new !