If you want to watch a DVD that appears to be ruined by scratches, there is one salvaging method you may not have considered. Grab the peanut butter from the pantry and have one last go at making the disc watchable.
Culinary blog Chow says that all you need to do is rub a little bit of peanut butter into the surface of the disc gently, let it sit for a minute, and then remove it with a soft cloth or tissue. Your mileage will vary, but it should at least reduce the odds of the DVD skipping while you watch.
So why peanut butter? Apparently, the oils in it can temporarily smooth out the disc's surface. Just make sure you're using smooth peanut butter and not the crunchy version! If you don't have peanut butter on hand, you can also try to remove the surface scratches with furniture polish, toothpaste or Vaseline.
How Peanut Butter Can Save Your Movie Night [Chow Tips]