Most tinked windows are not supposed to have commercial window cleaner used on them because the cleaners have ammonia (sp?). You could try a little bit of ammonia or windex on a very small corner area of the window and see how it works.
The other info that jjd said sounds good and I'd give that a try, but I would be very reluctant to use any kind of steel wool on any glass. Once its scratched its almost impossible to find anyone that can buff it out.
Also, you could try some laquer thinner or acetone. Be very careful with both of these around any painted areas or rubber areas. I use to use acetone to clean up fiberglass boat hulls. On glass or fiberglass the acetone will be the strongest, but one little drip on any paint, leather or vynal (sp?) and you'll have a problem. Also, keep the area WELL ventilated.

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95 GT Convertible
BBK shorties, X-pipe, Magnaflow CB
CAI, 70mm TB, GT40 intake, 1.7 RR, UD pulleys
SFC/braces/JR, AUC Arms
1966 C Coupe - New restoration project
2004 Chev Silverado 4X4