[Goat Blower]

It's hard to do, glass is a lot harder than paint. Steel wool won't do anything to glass, it actually works well for scraping bugs off windshields. Basically, about the only thing you can do is get the coarsest glass polish you can find and use a high speed buffer, similar to buffing paint. It takes a lot of work to even get out light scratches, much less a full windshield. You're best off having glass coverage on your insurance policy and "waiting" for a big rock to hit it.