Go to Concorde and see if they still have Pylon's Strip-It. Review can be found in theveed's PAD forum.
Alternatively, you can also try AutoSol Metal Polish (Yup, metal polish).
If you have a buffer, mga 15 minutes lang iyan. If by hand, about one hour siguro for a windshield.
Technique:
Clean windshield first.
Apply product (little only -- siguro half a teaspoon to a teaspoon worth for a whole windshield). Surface my be misted with distilled water (slight misting only!). Work product in until it practically disappears.