so I have a couple of these for my Trekker . Both are ok , but have scratches on the glass ... So I decided to try "fix" the worst one .. This one was from a unit I parted a few years back .. It was rolled , as you can see the deep scratches on the glass . so first .. I put some tape on the back side , so I would know ware I'm working then I brought out the DA and started to sand it with 220 it as far as I got today .. .