The first rule is, always hold discs by the edges using your fingertips only. (The center edge is OK too.) Even more than scratches, fingerprints are your DVD player's major enemy, so grabbing them like a frisbee is not a good idea. A smudge or fingerprint is very likely to block the laser which reads the disc and to cause your movie to freeze. If you do accidentally get a smudge on the play surface, use a soft, lint-free cloth dipped in rubbing alcohol to wipe it off gently. Wiping from the center to the outer edge of the disc is best.
The second rule is, your disc should be in one of three places only at all times: 1) in the case; 2) in the player; on its way between the two. Please note that this list does not include the coffee table, the floor, the dog's mouth, etc.
If you follow these two rules, everyone should be happier: you, us, and the next customer who rents the disc. If you hold discs by the edges and don't set them down anywhere but in the player or case, they should remain in good condition always. Although Jet does have a DVD resurfacer which can buff out scratches, we actually can only run discs through it so many times before they get worn out and have to be replaced. So help us serve you better by taking care of your discs! It'll leave us a bigger budget to purchase your DVD requests for you. ;)