[PANAVIA]

you could also probably find a polarized slip of film and do the tint trick.

remember polarized has an effective angle and usually there is a 0 degree and a 180 degree mark on the film. you can test this with two slips of film and tip them at 90 degree angles from each other.

one angle you can see through both angles, one angle they "black out" --to have the best reduction in glare, the orientation marks should be at 0-and 180 west and east on a compass if you will-- as if you were looking at a map on your mirror.