[QUOTE=Jedi Master Yoda;2099590]handling of the disc to go from drive to case was done be holding the edge’s of the disc and not touching the bottom.[/QUOTE]I don’t doubt that. Nevertheless, I have seen semi-circular markings (similar to what I see on the picture) appearing on the surface when manipulating the discs, even when handling the discs by the sides, and found that it was from the natural perspiration of my fingertips, specially when the weather is warm and my fingers aren’t top clean. They usually stay for a couple of seconds then disappear.
Maybe these marks can get semi-permanent in some cases, which was my conjecture.