If it was damaged id say yes, but if its over corrupt files....There are programs out there that can salvage these discs
http://www.naltech.com/
for example, but ya have to pay for them. If its just damage..
The cheapest way is using toothpaste. The best toothpaste to make your CD readable again is the toothpaste to make your teeth brighter, cause this scrubs better. You should be able to buy this in your local drugstore. You will have to rub with some cloth from the inside to the outside of the CD, in the opposite direction of the read direction of the CD.
If you have a really deep and big scratch, then you could use polish that is used by opticains on glasses. You should go to your optician for more information about this substance.