I spilled some on my neighbors dog and it went away!!! SERIOUSLY.....Try Coca Cola. YEARS ago, while stationed in Blytheville, Ark, I got some sorta mystery stuff on my old Camaro's windshield. Like you, I cleaned the hell out of it but I'd still see a subtle haze. I will say, it was very subtle but I KNEW it was there and it bugged me. My buddy told me to try Coca Cola. IT WORKED!! (It also cleans car battery terminals) Again, I have NO idea what was on my car at that time. The REAL funny thing was....2 weeks later, a rock broke my windshield and I had to get another one...sigh
