I have a beetle convertible. In winter I want to replace the optics with green tinted side/front panes. So far, so good … Unfortunately, I can buy the front rotating windows – also called triangle windows – only with slight defects: the windows are mounted at the top and bottom turnable so that they can be displayed. So, with the exception of the place where the discs are stored, the edges are visible. In the original, these edges are evenly cut round. D he offered me look like broken/cut. Can you grind the edges? How do you proceed?