Why do Chevy windows spot?
LOL Silly vanner, it's not a Chevy thing, all windows spot. It's the water. Clean them really good and treat them with one of the recommended products. I just wax them as I wax the van. It doesn't last long but it's easy and works great. Also go buy a new chamois, the synthetic ones work great and I've heard good things about the new microfiber ones. This will help with the spots tremendously.
I have scratched glass with a razorblade before so be careful, it's probably not the blade but the dirt it scrapes off getting dragged across the glass, but the result is the same. I have not tried the steel wool, that at least might make less visable swirly scratches with the dirt than straight ones with a blade, if any at all. I might have to try that someday.