some of my older cars have had the de-laminating headlight issue and essentially the best way I found was to
start with 1200 wet and dry then move to 2000
then use some cut and polish
then brasso....brasso makes it nice and clean and really good for cleaning plastuc up...in fact I use it on my ipod and phones all the time..
this should make it look nice...if not perfect. Don't rush it and spend a good 2 or so hours as effect = results.
KJ