A CD/DVD reader uses a laser beam to read the data on the
disk. This laser beam crosses the protective plastic layer and reads
the real recording metal layer. If the protective plastic layer is
scratched, the laser will be unable to pass resulting in non-readable
disc.

If somehow we manage to re-smooth this protective layer then the
laser will reach the data and read it, now there are many ways we can
achieve this using common household items as written below:

1). Toothpaste - Yups! toothpaste, you can use any non-gel based

toothpaste for this, just put a very small amount of it on the
scratched area and polish it gently using a cotton swab, sometimes the
paste may cause new minor scratches but they are just superficial. Now
just wash the cd using water.

2). If the above trick does not work try some metal polish like
Brasso gently wiping with a soft cotton ball followed by application of
Vasaline.

3). Baking Soda - make a small quantity of baking soda paste and
apply using a soft cotton cloth buffing the bad scratch. Clean the
baking soda before using the disc.

4). You can also try using some oil as a polishing agent this also works many times.

there are many daily use products that can be used to get the cd working just keep on experimenting.