Destroying optical media

You can get heavy-duty shredders that are designed to cope with discs. For example:

<http://www.primera.com/ds360_disc_shredder.html>.

And here's a gizmo that peels them:

<http://www.amazon.com/gp/product/B00064JJPM/102-4272572-0463336?v=glance&n=1064954>.

MD.

On 11/3/2006 11:24 AM, "Kevin van Haaren" <kevinvanhaaren.net> spake thus:

> I shred almost every piece of paper that goes through my house, even junk
> mail. But what is a safe way to get rid of CDs and DVDs? I almost took a
> plastic piece in the eye trying to break them in half. I finally ended up
> wrapping them in a towel and breaking them, but would like something a
> little better.

The better shredders will often also do CDs, but you're getting into
"office-grade" level in order to get that feature, at least of the ones that
I looked at recently. For example, I would have had to spend nearly five
times as much for a model that could handle CDs on top of all the usual
stuff. I went with the NZ$150 one that could munch staples and credit cards.

I've seen dedicated CD shredders advertised, but I can't get Google to
respond at the moment (probably local network congestion). I also came
across an industrial shredder company last year, who had a bunch of
demonstration videos on their site of their shredders munching things like
beds, washing machines and large chunks of reinforced concrete. That's
probably overkill though ;)

--
Nigel Stanger, Dunedin, NEW ZEALAND.
http://public.xdi.org/=nigel.stanger

Railway track

Disc(s) on track

Train.

Never had a recovery afterwards yet (grin)
--

  Peter Johnston, P Eng
  PSC Consulting Ltd.
  Email mailto:peterpsc-consulting.ca
  Sec. Email mailto:psccompusmart.ab.ca
  Telephone/Fax 780/459-9280

[Points for creativity! -Andrew]

On Mar 13, 2006, at 11:46 AM, Bill Rowe wrote:

> Another approach would be to use sand paper. Generally scratch up
> the surface of the optical disk and it will become unreadable.

Hmm... I could easily see polishing the optical disk to remove the
scratches as defeating this scheme.

Granted, it'd take some effort, but if you know the CD contains
valuable information, then it may be worth it, with little investment
in tools. Physically breaking the CD into tens of different parts,
some of them slivers (and missing), would foil just about anyone
without special tools.

I like the finality of the sound of snapping CD's (ever since
Brittany Spears'), but the creative destroyer in me says fire or acid
would do just as well. Though as Norm says at the beginning of every
episode, never forget your safety glasses. Wonder if Delta makes a
special tool for breaking CD's. Lord knows they seem to make one for
everything else ;-)

Matt

On 14/3/2006 6:47 AM, "Nigel Stanger" <nstangerinfoscience.otago.ac.nz>
spake thus:

> I also came across an industrial shredder company last year, who had a bunch
> of demonstration videos on their site of their shredders munching things like
> beds, washing machines and large chunks of reinforced concrete.

Our network's recovered today, so here's the site with the shredding movies.
Watch a BMW get shredded! Fun for the whole family :)

<http://www.ssiworld.com/watch/watch-en.htm>

--
Nigel Stanger, Dunedin, NEW ZEALAND.
http://public.xdi.org/=nigel.stanger

Assuming single-layer media, the way to scratch away data is to make "with the grooves" scratches on the "back" side. This is where the actual data is, and in fact, CD's and DVD's are more vulnerable to accidental damage on that side that on the side from which the data is read. Scratching with the grooves (rather than radially) is more damaging because it makes it much more difficult for error-correction algorithms to reconstruct a few missing bits.

On Mar 13, 2006, at 9:43 PM, Peter Johnston wrote:

> Railway track
>
> Disc(s) on track
>
> Train.
>
> Never had a recovery afterwards yet (grin)

Citation from local police for littering.

Citation from railway special agent for trespassing.

Fear that flying splinters will damage an innocent bystander
(presumably you've left to avoid the first two).

I've seen people use CDs as shotgun targets.... Pull!


--
-- Marshall

Marshall Clow Idio Software <mailto:marshallidio.com>

It is by caffeine alone I set my mind in motion.
It is by the beans of Java that thoughts acquire speed,
the hands acquire shaking, the shaking becomes a warning.
It is by caffeine alone I set my mind in motion.

I had been collecting CD's and DVD's because I didn't know how to destroy
them myself, until I purchased a Primera 360 Disc Shredder.
  <http://www.primerastore.com/DS360>

It looks like a
smaller paper shredder but in fact it eats CD's and DVD's pulling them
inside and literally fractures them into tiny plastic pieces inside the
unit. Its designed for heavy duty use, and does bulk at eating a hundred
discs one after another. Costs about $60, and warranted for 3 years. I'd
recommend it.
Todd

Matthew Clay Childress wrote:

> On Mar 13, 2006, at 11:46 AM, Bill Rowe wrote:
>
>> Another approach would be to use sand paper. Generally scratch up the
>> surface of the optical disk and it will become unreadable.
>
> Hmm... I could easily see polishing the optical disk to
> remove the scratches as defeating this scheme.

Depends on how you do it. On a CD, the data sits directly beneath the
label. Sand the label off and no amount of polishing (nor any other
method) will recover the data. A DVD is harder to get rid of; IIRC its
data is sandwiched between two layers of plastic. Still, you could use a
belt sander to grind the entire DVD to dust.


Harro de Jong

On Mar 10, 2006, at 5:24 PM, Kevin van Haaren wrote:

> I shred almost every piece of paper that goes through my house,
> even junk
> mail. But what is a safe way to get rid of CDs and DVDs? I almost
> took a
> plastic piece in the eye trying to break them in half. I finally
> ended up
> wrapping them in a towel and breaking them, but would like something a
> little better.

There is a product that does precisely what you ask: a media
shredder. Royal makes one:

http://www.royalsupplies.com/products/SHR/29064J.html

I'm sure there are others. But at $90 it's a bit steep. Also a lot
of paper shredders for the SOHO market (not the flimsy 2 sheets-at-a-
time home use kind) have media shredding capability these days.


On Mar 14, 2006, at 12:43 AM, Matthew Clay Childress wrote:
> I like the finality of the sound of snapping CD's (ever since
> Brittany Spears')

The problem is that while music CDs will generally snap, CD-R media
(and I presume DVD-R as well) tends to shatter when bent past its
breaking point.

Lots of little bitty pieces flying all over the place is great for
data-security, but not so great from the cleanup or (as Kevin
mentioned) physical safety perspective.

But given the propensity of the media to shatter, maybe a paper bag
and hammer would work. Put all the disks to be destroyed in a paper
bag, whack the bag multiple times with a hammer, verify you got the
desired results.

Tomoharu

>
> Put them in a microwave oven for about two seconds.
>

Three people suggested this. Do any of you actually use these microwaves
for food afterwards? Seem there would be an interesting mix of long
hydrocarbons and other things deposited as seasoning. :)

Even faster than taking out a pocket knife or a screwdriver sometimes is
putting the media on a rough surface and stepping on the disc and rubbing
it back and forth a few times. It causes a lot of random scratches and
certainly gives a visual clue that the data will be more challenging for
the snooper to try to resurrect. I don't know how effective it is, but it
certainly looks good and is actually a bit fun.

An outdoor concrete sidewalk is the best. The next best thing (for those in
office buildings) is the grooved, etched areas at the top of each step in a
commercial stairwell.

John Connerat

On 3/13/06 at 9:43 PM, mccprairienet.org (Matthew Clay Childress)
wrote:

>On Mar 13, 2006, at 11:46 AM, Bill Rowe wrote:

>>Another approach would be to use sand paper. Generally scratch up
>>the surface of the optical disk and it will become unreadable.

>Hmm... I could easily see polishing the optical disk to remove the
>scratches as defeating this scheme.

Whether you could polish the disk and recover the data would depend on the details. If I were to use a fine grit sand paper on the non-label side, then yes, quite likely you could restore the disk to readability by polishing it. OTOH, if I used a coarse grit sand paper on the label side, it is unlikely disk could be restored by polishing.

On 16 Mar 2006, at 06:36, Todd Naber wrote:

> I had been collecting CD's and DVD's because I didn't know how to
> destroy
> them myself, until I purchased a Primera 360 Disc Shredder.
> <http://www.primerastore.com/DS360>

How small are the pieces?

I wondered if you could recycle them as light weight bulking for
concrete mixes :0]

Drew

At 22:36 03/15/2006 -0800, David Ross wrote:
>Three people suggested this. Do any of you actually use these microwaves
>for food afterwards?

Yes, with no qualms.

>Seem there would be an interesting mix of long
>hydrocarbons and other things deposited as seasoning. :)

I don't have any solid (so to speak) information on this, but I doubt it's
a problem. As I understand it, the concentration of radiant energy around
the metal surface causes sudden changes in temperature which fracture the
metal. Possibly it also causes electrical gradients -- I don't know if the
sparks are thermal or electric.

The substrate is polycarbonate. I use glasses and cups made of
polycarbonate in the microwave -- they are labeled as microwave-safe.
Polycarbonate can withstand the thermal gradients of normal microwave use,
whereas acrylic (also often used for dishes) cracks.

So the only thing left as a possible problem would be the lacquer on the
surface, inks and adhesives, etc.

And finally, very little material vaporizes in the time the disc is being
treated. Mostly it just crazes the metallic coating.

All that said, for all but very low volume use, I'm sure that a shredder is
a great deal more convenient. But as others have pointed out, it's still
worth understanding the construction of a CD so that you can evaluate the
techniques.

Oh, and as yet another note, if you're using DVDs for backups, encrypt the
backup using DES and a good key. Then you don't have to worry about
destroying them.

Edward
Art works by Melynda Reid: http://paleo.org

Since you mention "House", I'll assume that we're not talking about national-security-level secrets here. In that case, what you want is an inexpensive pair of aviation snips (sometimes also called tin snips). They're kind of like scissors on steroids (they cut less material per snip, but transmit much greater pressure to cutting edge). They make short work of CDs/DVDs.

Here's an example <http://www.mytoolstore.com/klein/1102s.html>, but they're available from any hardware store.

- Alaska Jack

Edward Reid wrote:
> At 22:36 03/15/2006 -0800, David Ross wrote:
>> Three people suggested this. Do any of you actually use these microwaves
>> for food afterwards?
>
> Yes, with no qualms.
>
>> Seem there would be an interesting mix of long
>> hydrocarbons and other things deposited as seasoning. :)
>
> I don't have any solid (so to speak) information on this, but I doubt it's
> a problem. As I understand it, the concentration of radiant energy around
> the metal surface causes sudden changes in temperature which fracture the
> metal. Possibly it also causes electrical gradients -- I don't know if the
> sparks are thermal or electric.

Every time I read or hear things like this I think back to my high
school chemistry class. 90% of what we did would be totally forbidden
these days. And half the chemicals that we used to do "neat" things
would bring out the guys in moon suits now.

 > And finally, very little material vaporizes in the time the disc is being
 > treated. Mostly it just crazes the metallic coating.

And we really had fun with mercury. :)

I'm showing my age. ;)

On Mar 17, 2006, at 9:11 AM, anjtc wrote:
> Since you mention "House", I'll assume that we're not talking about
> national-security-level secrets here. In that case, what you want
> is an inexpensive pair of aviation snips (sometimes also called tin
> snips). They're kind of like scissors on steroids (they cut less
> material per snip, but transmit much greater pressure to cutting
> edge). They make short work of CDs/DVDs.

Safety glasses, if there is any connection with employment. Keeps
OSHA (or Washington's Labor and Industries) off your back, although
the chances of needing the glasses are small. And no kids or pets
around (employment or not).

   --John

try a drop or 2 of super glue. this will melt the surface, and it will all stick ogether.