Did you check the at nail varnish remover wasnt the accetone free one as if thats the case you could soak it in the stuff for days and wouldnt touch it.
If its sprayed on then you will have too choices wipe it off with solvents. Ie Methylated spirits, white spirit, Accetone, Celulose thinners depending on the base of the spray. Meths would be my first try as its less likely to do any damage. When I took the vinyl off the car I had to basically wash it with the stuff as left loads of residue everywhere.
Or sand it off with some fine wet'n dry and work your way up the grits and buff the lights up. As said wont effect the beam pattern, youd have to sand a hell of alot off to do that as the beam is focused from the inside. Its more time consuming for sure.
If the nail varnish remover definatly contained accetone (different from accetate
) then Id be tempted to try meths then as a last attempt thinners although do with care as its agressive on plastics and paint! Wash off with plenty of water afterwards. If all else fails petrol or brake fluid strip most things!!
Alternatively E-tech sell a tinting spray remover
which will have a base of one of the previously mentioned chemicals.