cliffs notes: i live in the city; my parking space is also in the same area as restaurant's kitchen exhaust is from. over the years, i've accumulated this film over my windshield that I'm unable to remove.

I've already tried: alcohol, invisible glass, mother's clay bar, windex, bug/tar/sap remover. None have worked.

It looks like there are streaks running down my windshield. The visibility is horrible in the rain. When oncoming headlights hit the windshield in the rain, it scatter light everywhere and it pains me to drive.

any suggestions? i thought about using one of the hand held steam cleaners that you see on television; supposedly they cut oil and grease on kitchen stoves. i don't know if that will work - I'll have to buy one to find out.

 

I've never used on of the hand-held steam cleaners, but it sounds like a reasonable idea (it also sounds like you have tried almost everythying else).

If that doesn't work, I would replace the windshield and send the bill to the restaurant....

 

Best stuff I've used for heavily marred glass is 0000 grade steel wool. I use a cleaner wax applied with the steel wool then buff off with a microfiber. So far it's worked on every car's glass I've detailed when nothing else will.

Note of caution: steel wool isn't so good for paint, so keep it away from the rest of your car.