How To Save A Scratched CD ??

How To Save A Scratched CD ??

          How could smearing a paste on the surface of your CD save the data that lies within? Why not just dip your CD in ketchup, jelly or dish soap for that matter? The truth about the toothpaste claim comes out when you take a look at how a CD actually works.

          Each of the major layers of a typical CD are displayed here. When you flip over a CD and hold it up to the light to look for a scratch, what you’re looking at is the “thick” Polycarbonate Plastic Layer. The word thick in used, because it is 1.2 mm.

Now, when you play a cd , you are actually reading it using the Laser light . The data in a cd is arranged in terms of pits and lands (analogous to 1's and 0's) in Aluminum Layer. So the data is not stored in the outer layer of the cd as many think but in one of the inner layers.

If you follow the path of the laser beam through the clear plastic layer, you’ll see that it strikes the aluminum (or reflective) layer. This layer bounces the light directly back to the CD reader. As the CD spins, the time it takes for the light to reflect and return tells your CD ROM whether or not there’s a “pit” or “land” (Obviously the time taken for light to come back from a pit is more).

As the CD spins and the laser is busy scanning the pit data pattern along each track and decoding the information, when it hits a significant scratch in the polycarbonate surface, the laser beam is deflected just enough so that the pit data pattern is misread.

Now, normally for very small or occasional scratches, this isn’t a huge deal because the data on the CD and the CD drive circuitry has an integrated error-checking code system to handle the occasional misread bit here and there. However, when the scratch is significant enough so that the laser beam misreads a large batch of the track, the disk either skips or becomes unreadable.

Toothpaste To The Rescue :

A lot of people testify that rubbing toothpaste (either with a soft cloth or a cotton swab) along the scratch has the ability to correct the problem described above. Does this really work, and if so – why? The answer is: Yes. It works, and it works well.

First, when you place a dab of toothpaste on the scratch (preferably baking soda or other “gritty” paste, not gel) and rub the paste into the scratch from the center of the CD outward, you are essentially “sanding” down the imperfection on the surface of the polycarbonate plastic layer. By sanding away the imperfection, you’re removing deflection of the laser beam, and by doing so you’re correcting the problem. Of course, before you attempt to do a “toothpaste buff,” always make sure to wash off any dust and fingerprints from the surface of the CD.

Now dry it off with a soft cloth, and always wipe the CD starting from the center and outward toward the outer edge of the CD. This will reduce the chance that you’ll introduce any additional scratches across multiple tracks. Once the CD is clean and dry, you’re ready to buff the surface with toothpaste.

Apply again a dab of paste (not gel) to a cotton swab or soft cloth and apply it directly to the scratch. Rub the toothpaste in small circles (like you’re buffing a car) along the length of the scratch.

After a while, you’ll notice that while you’ve created some very fine surface scratches, the deeper scratch has either grown faint or entirely disappeared. Don’t apply too much force when you’re “sanding” the scratch – a gentle circular motion is all you need to buff it away. When you’re satisfied that the scratch is either gone or reduced enough to make a difference, put the CD through another gentle rinse and dry.

And thus it is possible to fix a scratched CD with toothpaste!