# Fix a Scratched CD



## lotuseclat79 (Sep 12, 2003)

Fix a Scratched CD.

When I bought the book, Knoppix Hacks (O'Reilly) w/a Live CD (version 3.4), I used a pocket knife to open the (very tightly packed CD) and scratched the working surface of it.

Advice: If you are facing the same situation, try to make sure your knife is inserted into the envelope containing the CD on the top surface, so if you do scratch the top surface of the CD rather than the working surface (shiny mirror like surface to be read by laser), the working surface can remain intact and will probably work.

I am going to try the last technique as it appears to be the best in my situation - i.e. Meguire's Deep Crystal (cleaning system) Paint Cleaner.

Let us know whether your attempts succeeded at trying any of these techniques. I will when I give it a try in this thread.

-- Tom


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## JohnWill (Oct 19, 2002)

lotuseclat79 said:


> Advice: If you are facing the same situation, try to make sure your knife is inserted into the envelope containing the CD on the top surface, so if you do scratch the top surface of the CD rather than the working surface (shiny mirror like surface to be read by laser), the working surface can remain intact and will probably work.


WRONG! The actual information is RIGHT below that surface of the label, and that side of the CD/DVD is MUCH easier to damage. The clear plastic layer is deliberately thick to allow the laser to focus on the data pits and to be out of focus for the smaller scratches on the clear bottom side. If you damage the label side, you can truly toss the disk, there will be no recovery. There are many methods to recover from scratches on the clear bottom side.


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## valis (Sep 24, 2004)

Yup. That's actually how we destroy data disks here (when I just don't shatter the damn things); key the top of the disk, it's useless.


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## Stoner (Oct 26, 2002)

I get many movies from the library and with all the use they see, scratches are too often evident.
I've been able to get most of them to play with out stopping or skipping after polishing with toothpaste and a lens cleaning pad.

Scratch the back and game over......it's not going to play.

I destroy my data CDs and DVDs with a cheap set of scissors......three radial cuts spaced out equally is also a 'show stopper'


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## lotuseclat79 (Sep 12, 2003)

JohnWill said:


> WRONG! The actual information is RIGHT below that surface of the label, and that side of the CD/DVD is MUCH easier to damage. The clear plastic layer is deliberately thick to allow the laser to focus on the data pits and to be out of focus for the smaller scratches on the clear bottom side. If you damage the label side, you can truly toss the disk, there will be no recovery. There are many methods to recover from scratches on the clear bottom side.


Hi John,

Thanks for that information. However, on my scratched CD, the outer edge of the back (working surface) of the CD was scratched for about an inch. Yesterday, I used my 2nd CD drive (while booted into my Live CD environment) to copy all of the mounted CD's directories and files over to a directory on one of my disks - and got a good list of what is missing.

The side I am talking about that is damage is not what you call the label side, i.e. it is the mirror (shiny) side. There is nothing scratched on the label (front) side of the Knoppix CD.

-- Tom


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## valis (Sep 24, 2004)

Stoner said:


> I get many movies from the library and with all the use they see, scratches are too often evident.
> I've been able to get most of them to play with out stopping or skipping after polishing with toothpaste and a lens cleaning pad.
> 
> Scratch the back and game over......it's not going to play.
> ...


toothpaste? Hadn't heard of that one. Would have thought it was too granular........I'll have to give that a shot.......thanks, SJ. :up:


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## Stoner (Oct 26, 2002)

valis said:


> toothpaste? Hadn't heard of that one. Would have thought it was too granular........I'll have to give that a shot.......thanks, SJ. :up:


Just make sure it's a creamy paste without harsh abrasives....I use Crest regular.


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## valis (Sep 24, 2004)

man, never heard of that one before......have to try it on one of monkeyboy's flicks, as he is a bit rough on them.


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## JohnWill (Oct 19, 2002)

lotuseclat79 said:


> The side I am talking about that is damage is not what you call the label side, i.e. it is the mirror (shiny) side. There is nothing scratched on the label (front) side of the Knoppix CD.
> 
> -- Tom


OK, it sure sounded like you were talking about the label side, that's the *kiss of death* if you damage that to any degree. As I mentioned, on the other side, I've recovered some REALLY ugly ones with my buffer, and it's pretty quick too.


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## valis (Sep 24, 2004)

what buffer do you use?


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## JohnWill (Oct 19, 2002)

I use a bench buffer with 8" buffing wheels. I use the soft one for CD/DVD repair, and some generic plastic polishing compound. I polish radially from the hub out and just work the disk around to get the whole thing until the big scratches are gone.


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## Stoner (Oct 26, 2002)

What spindle rpm do you spin the buffer?
And where do you get the plastic polishing compound?


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## JohnWill (Oct 19, 2002)

Well, it's a 3600 RPM buffer, so that part is pre-determined. I get the polishing compound at the local hobby shop, it comes in stick form and you just apply it to the buffing wheel sparingly. The amount of "polishing" is determined by the pressure you apply. On really bad scratches, I have started with the stitched "hard" cloth wheel at first, then move to the "soft" wheel, which just has a bunch of separate cloth pieces bundled together. These are standard buffing wheels that you can get at most tool stores.


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## Stoner (Oct 26, 2002)

Any problems with 'burning' the disk?
Looks promising....think I'll save up a few throw away discs to experiment with.


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## JohnWill (Oct 19, 2002)

No problem at all burning the disk. I've done half a dozen, mostly movie DVDs that my grandson has "used" and "abused", and one music CD. If you are gentle with the buffing wheel, it works just fine. I've actually gotten pretty aggressive on a couple that were really scratched, and they survived to play again.

I've yet to try it with a disk I've burned, these were all commercial disks, though the results should be the same.


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## itsjusme (Aug 19, 2006)

valis said:


> Yup. That's actually how we destroy data disks here (when I just don't shatter the damn things); key the top of the disk, it's useless.


LOL: Yeah, but the guys at the CSI lab can still recover data from it, you know, the same people that can get DNa results in 5 minutes! If you want to permanently destroy data on a disk where it is impossible to recover any of it, and make a pretty good conversation piece at the same time, stick it in the microwave for a few seconds. As soon as the light show is over, stop. It`ll stink up the house pretty quick if you keep cooking it.


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## itsjusme (Aug 19, 2006)

JohnWill said:


> ................................................................................
> I've yet to try it with a disk I've burned, these were all commercial disks, though the results should be the same.


Commercial disks have a protective coating that is a little tougher than the consumer grade disks we use( at least i`ve read that and it seems to be true, consumer grade disks scratch really easily), they seem to stand alot more abuse without scratching. But you are right, the results are the same. I have tried many things besides buying a machine to repair them, although they`re not that expensive anymore. (anywhere from about 19.95$ to several thousand) I now use automotive grade wet or dry sandpaper (wet) in steps up to 2000 grit, and then polish with superfine buffing compound, high speed buffer and light pressure. I have also tried the toothpaste ( we used that to polish our class rings in high school: LOL ) and the Meguiars plastic polish which worked. I have also sanded out the scratches and sprayed the disk with clear lacquer( thinned at least 50/50, very light coat) , that worked well providing you can keep the bugs and dust off. Once the lacquer cures, it leaves a surface tougher than the plastic of the disk. I`ll try anything sometimes to salvage one of my old classic movies that i had a hard time finding.


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