My windows fogged up big time the other day and I noticed a big circle on all the windows. The windshield had four. I thought I did a good job of cleaning my windows. They only show up when the windows fog up. Anyone have any ideas?

 

Try a solution of 50/50 water/vinegar. Don't get any of the solution on any of the vinyl (dash or doors). If that doesn't work try a glass polish. If all else fails try steel wool (0000 grade) just on the marks themselves.