Never had one of the windshields but should be able to use a good quality microfiber and Stoner Glass Cleaner. How To Clean Glass | Glass Cleaner | Invisible Glass
I clean my headlights both quad and cars/trucks with it and clothes, then buff them up with layers of Megiuars NXT 2.0 liquid wax. Buff clean and clean, makes it very water/mud repellent, and any dust usually washes off completely with just a garden hose. Could also try their Scratch X stuff for plastics to see if that can restore your old one!