To be honest i just did mine which were much worse than the ones in these pictures.
I used a high speed buffer and 3M part# 05933 perfect-it #3
it is a very fine cutting compound to buff paint.
1) put on a thin coat and use the buffer carefully on the light fixture for a few min.
2) wipe it all off to inspect the spots you missed, then do it again to finish it again.
3) use a good wax like Zmyol to seal the plastic or the problem will return rather quickly.