1) Use a yellow highlight marker and draw it over the scratched area. Careful, dry tips can scratch the disc. 2) Sprayable “silicone oil” - sold in Europe as “cockpit spray”. I read it has a good affinity to the hydrophobic plastic material and a similar refractional index, which is the point! Similarly, silicon spray will work. It should look like a mirror finish, but if you use too much the disc will be unreadable. Try spraying a tiny bit on and rubbing it over the surface with paper towel - you’ll see it ‘hide’ the scratches as you rub. If you put too much on, it comes off pretty easily with eye glasses cleaner or other mild glass cleaning agent. 3) Toothpaste, with its abrasive particles can work their way into the scratches. Use a small pointer to rub it into the scratches to bring them closer to the surface and more even with the rest of the disc. Just make sure to clean off the disc when done. You don’t want toothpaste flying around your DVD drive. 4) Try cooling the disc. If that doesn’t work, try heating it. This trick will often help you get some more sectors read. 5) Some have had success with car wax or car polish. Worth a shot if all else fails.