CDs get a lot of scratches over time. Here's a little trick that may help.

"Warning" this may not work if you ex-girlfriend took an icepick to your cd..LOL

Steps

Get your supplies (listed below).

Squirt toothpaste around the scatched CD.

Take the face cloth (or towel) and wipe the tooth paste around. Use a circular pattern, don't rub too hard, but work the scratched area over well, and then wipe it off. Wipe from the centre of the disc to the outer edges to prevent further damage to the disc.

After all toothpaste is gone you're good to go.

Repeat steps 2 and 3 if necessary.

An alternate method for severely scratched CD's is to apply a very thin coat of vaseline to the readable surface and wipe with the face cloth to fill in the scratches (this is a temporary fix only and a copy should be made immediately).

Supplies:

face cloth
cd
tooth paste
lots of spare time

More useful Tips

Use cheap toothpaste (you need quite a bit).
Don't use the clear gel type.
You might also try to copy the whole CD if you have a burner on your computer. Your computer can often read the CD correctly even when your CD player skips.
In the case of a data disc, the contents may take a very long time to read, increasing wear on the disc. It may be a good idea to create a backup immediately to prevent total data loss.
Warnings
This doesn't always work but it should make a difference. Scratches will be there but it won't skip anymore.