Erasing CD-R and DVD±R


H

HelenF

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There are a lot of posts around the internet where someone asks if it's possible, and people reply with "no" or "what's the point? just break or microwave it".

When writing the data, the write laser burns some of the dye and leaves some of it alone, and this is not reversible. But overwriting the unburned areas would destroy the data pretty effectively. There might still be traces available for forensic recovery, but it's clearly better than just breaking the CD (which leaves most of the data intact).

I don't see a reason why the hardware of any drive couldn't do this. It seems to me that it's the drive firmware which prevents overwriting write-once media.

Wikipedia:CD-R says (added in 2010),

Some recent burners (Plextor, LiteOn) support erase operations on -R media, by "overwriting" the stored data with strong laser power, although the erased area cannot be overwritten with new data.
Click to expand...
There was various news around the internet about Lite-On drives which could do it in 2008 (iHAP322, iHAS322 and iHAS422):

http://www.techworld.com.au/article/267105/erase_your_discs_lite-on_smarterase_/

2009 news about eHAU324 saying it features SmartErase:

http://www.liteonit.eu/en/news-and-events/lite-on-introduces-24x-external-dvd-writer.html

A Lite-On download page offers a program called Smart Erase, which says it supports iHAS324, iHAS424 and iHAS524:

http://www.liteonit.eu/APPS/download_utilities.html

Unless I'm missing something, the product page for iHAS324 doesn't mention it at all...

http://www.liteonit.eu/en/optical-storage-dvd-rw-internal/ihas324.html

The product pages for new models also don't mention it. So has it been abandoned, or is it now a standard feature that they don't think is worth mentioning?

I emailed Lite-On to ask about this, and they unhelpfully replied, "For the product specification or information please kindly refer to our official website".
 
I've never been paranoid enough to care that someone may piece together the tiny pieces of a CD or DVD when I put it through the shredder. usually I do this in bulk, so good luck for the one trying to do that. 
 
Burning or microwaving is bad for health and safety, and means the CDs can't be recycled afterwards.

What sort of shredder actually cuts a CD into tiny pieces, and how much do those cost? The regular ones in the shops have a separate slot for CDs that only cut into 3 or 4 pieces, so might as well just break it instead.

(And from the super-paranoid perspective, how much data is on a single one of those tiny pieces?)

http://www.paleotechnologist.net/?p=165
 
HelenF said:
What sort of shredder actually cuts a CD into tiny pieces, and how much do those cost? The regular ones in the shops have a separate slot for CDs that only cut into 3 or 4 pieces, so might as well just break it instead.
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Not sure, it's built onto the office shredder at work and it shreds very fine, it has a separate slot for shredding CD/DVDs and credit cards. I have seen home units that can shred CD/DVD and credit cards too, just not sure how fine it is.   
 
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But breaking up old CDs etc. is fun!  I do it in a sturdy fabric bag, to capture all the pieces that can fly off.  I've also notices that if you just stress them enough to crack one layer, you can pull them apart - protective layer on the underside, reflector up top.  It tends to split where the dye is, and it's still fluid in all the discs I've disassembled, so it's easy to smudge it then if you've really got something you want to keep secret.
 
A live volcano is the answer.


What you do is...hours before it erupts in a blazing spectacle, you fly (helicopter) high above it and drop all your CDs/DVDs/BDs into the lava and shit.


Done.
 
Back when I had to destroy outdated sensitive stuff weekly I used scrape the data layer off on pavement, and/or shred them, and/or burn them.  I feel like there were times when we did all three, but our shredder was one of the ones that essentially powders paper, and we weren't supposed to use it for anything but a single piece of paper at a time, and only for paper, to prevent damage or jamming.  It wasn't small, just designed precisely to leave nothing readable or that could be reassembled.  It was 6 feet tall, and some people that I had not instructed on how to properly use it assumed that a big shredder with a big hole to put stuff in the side meant you could throw a whole box in at once.  There were several times we had stuff pile up while it was jammed for weeks at a time until authorized people could repair it.

So, yeah, if you want the data gone and to recycle it, if that is allowed, scrape the back side on pavement.

Edit:  Instructions:

1. Put on old boots.

2. Grab disc to be "erased".

3. Go outside.

4. Realize that the people outside don't like seeing you wearing only boots, go back inside, cover your nakedness then go back outside.

5. Find a sidewalk or something.

6. Put disc on sidewalk with shiny side up.

7. Stomp on disc.

8. Push down with toes, or heel maybe.

9. Twist and slide the disc around on the pavement with boot until you are satisfied with the results.
 
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SONY said:
A live volcano is the answer.
Click to expand...
b7hwz9.jpg



It's the only way.
 
CDs are made of very mouldable material, hold it on a lighter for a second and you can blow bubbles. 

You get a soap bubble that never pops. 
 
You can scratch the surface (not the bottom) with hard sandpaper. You need to scratch it very hard though.
 
If you destroy the relector (of a recordable disc) you will stop it being read, but won't destroy the data.  On those discs (unlike on mass produced CDs, CD-ROMs or DVDs) the data's actually held in the dye layer, a little below the reflector.  If you've only damaged the reflector, that can be taken off and replaced, in theory at least.
 
Levi said:
If you destroy the relector (of a recordable disc) you will stop it being read, but won't destroy the data.  On those discs (unlike on mass produced CDs, CD-ROMs or DVDs) the data's actually held in the dye layer, a little below the reflector.  If you've only damaged the reflector, that can be taken off and replaced, in theory at least.
Click to expand...
Does this mean that my instruction listed above won't remove the data?  Just curious if there is a simple way to wipe and recycle it.
 
I suspect not indeed, although it would take rather a lot of work to get the data off them after a good grinding.

I'm not sure what is needed to recycle old discs.  Are they just melted down, or do they still need to be disc shaped?  I don't think my council takes old cds.

I wonder if pointing an IR laser pen at them would be enough to modify the photosensitive layer, or whether it'd need to be focussed to do anything.
 
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