The CDR is a pretty robust storage medium, but it is susceptible to scratches. We’ve had a few readers inquire about ways to retrieve data from or repair scratched CDR’s. Here’s what we can tell you.
If you scratched the top (label) side of a CD-R, and it no longer works, your disc is basically a coaster (ruined). If you scratched it, and it still works, copy the data off while you still can. If you scratched the bottom side, then all you’ve done is etch the polycarbonate (plastic), and it can be repaired. A common misconception is that the data is on the bottom, but if you examine it carefully you will see that the data is beneath the label. The laser reads the data through the polycarbonate layer, and if the layer is scratched the laser will refract onto the wrong part of the disc. For small or radial scratches, the error correction in the CD format will allow the disc to continue working, but if there’s too much disruption you will get audible glitches or CD-ROM driver errors. If the disc works some of the time, you can “repair” it by copying it onto a new CD-R disc. If the disc is always unreadable, or is copy protected, you will need to repair the disc itself. There are two main categories of disc repair:
- Mild abrasives: plastic or furniture polish, Brasso metal polish, and toothpaste. These will totally remove minor scratches.
- Fillers: turtle wax, car wax, furniture wax. Apply over the whole disc and buff out with a lint free cloth. Filling larger scratches should be fairly effective but the disc will be more prone to damage in the future due to the soft wax.
One product that may be useful is Wipe Out, a chemical abrasive that allows you to reduce scratches. There are also some services on the Web that specialize in disc repair, but they can get fairly expensive.
When cleaning a disc remember not to wipe in a circular motion. This can produce scuffs and scratches that are more severe to the laser. Only wipe in a straight line from the inside to the outside of the disk.