This method is the most extremely effective way on bringing back unreadable and heavily scratched CD's but a word of CAUTION! it is also the most risky and dangerous!

You need the following to begin with.

1. A Gas Stove
2. Cotton Towel
3. Pot with 2 inch of water.
4. Fork.

Step 1: Position the Fork Into the CD.

You need to insert the two tooth of the fork into the center of the CD.
Make sure that the fork doesn't change the CD's contour too much, and it must be straight and even.

Step 2: Carefully Heat the CD Into a Low Flame.

You must take extreme care with this process, since it'll easily destroy your
CD if you have no control. Spin all around the CD into the flame, until the heat
is evenly distributed.

The CD will slightly bend in the middle and in it's sides, but not too much, else the CD
is all f*cked up.

Step 3: Boil Your CD.

Boil the CD for 5 minutes, so the uneven sides will be contoured by hot water to straighten up. Cover it.
The CD will float by the boiling water, so don't worry about it touching any hot metal surfaces of the pot.

Using a fork, fish the CD out, then put it in a towel, where you dry it up from the center outwards.

And it's done!
The CD is as good as new!