If a magic eraser doesn't work you might try window cleaner and newspaper. It almost, but not quite, looks like the milkiness that was on my windshield when I bought my dart that had been parked for years. My windshield was mottled/patterned looking though.... where the condensation had been and dried then repeated the cycle for who knows how many years. I used regular window cleaner and newspaper to clean mine. There is something in the ink in newspaper that shines glass. Just don't use the colored or glossy pages of the newspaper.
