Can anything be done for a cd that keeps getting "cyclic redundancy check?"

[ChromeFoundry]

3. Polish the surface...

I don't suggest doing this on a BluRay or DVD, but on a CD I've had luck...

Wash the disc with a mild dish washing liquid.
On a damp soft cloth, add a small dot of toothpaste (gel works best).
Lay the disc on a clean, smooth, flat, sturdy surface.
from the center hole to the outer edge (radius), rub the toothpaste back and forth on the disc, pressing fairly hard.
(Never, never, never polish in a circular manner or any direction that is not along the radius of the disc)
slightly rotate the disc in a clock-wise manner after about 10 back and forth cycles.
(keep the cloth damp and add more toothpaste as needed)
repeat until the entire disc surface has been polished.
Wash the disc with dish washing liquid, again.
Dry the disc off before sticking it into the reader.

CRC errors are commonly caused by small scratches that follow the tracks on the disc. This will buff away small scratches and allow you to get a backup - usually.