Cleaning and repairing discs
Cleaning a DVD should be done with a soft lint-free cloth. Wipe radially away from the hub, don't follow the curve of the disc. For particularly hard to remove dirt you can use lukewarm water and dish soap, but make sure the disc has dried properly before inserting it in the player. Normally this won't cause a problem, but in the case of a disc suffering from layer separation this can actually destroy what's left of the disc. Try a cloth first.
Scratches can be repaired using products such as disc doctor which actually grinds down and polishes the scratch to a point where the data is readable again. A rather well known trick is to use toothpaste to grind out the scratch:
- apply a small amount of toothpaste to your fingertip
- rub the toothpaste radially over the scratch until it's ground down
- remove the toothpaste using tissue paper (you might also have to use soap and water, see above)
- test the disc, and if it doesn't work try it again
No Blu-ray, no buy. No lossless audio, no buy.