posted to the Roxio newsletters on March 22, 2000

It's easy enough to get data onto a CD-R disc, but what about getting it off? What if you have old backups or other data on disc, and you're afraid that if you simply throw the disc into the trash, someone will pick it out and have access to your valuable data? Destroying CD-R media is easy and fun, and there are several ways to accomplish the task, but always keep personal safety and the environment in mind.

Remember that a CD-R consists of a clear polycarbonate disc, with dye on one side and a reflective layer on the other. If the reflective layer, the dye, or the polycarbonate is sufficiently damaged, the disc cannot be read. So, one of the easiest ways to destroy a disc is to physically damage the polycarbonate itself. Simply cut the disc in two with scissors or a paper cutter.

NEVER try to destroy a disc by bending it between your fingers in an attempt to break it. Some will bend, but not break. Some will break in two. Some, however will shatter into flying shards of polycarbonate - ouch! This is dangerous, not only to yourself, but to any spouses, children, or pets which happen to be in the immediate vicinity.

Cutting the disc into two or several pieces is a quick and easy solution, but if you are really paranoid, you have probably already guessed that those crafty folks at the CIA and the FBI can probably put this disc back together and read most of the data off of it. Recently a man was convicted of murder, partly on the basis of information contained on a floppy diskette that he thought he had destroyed by cutting it to pieces with a scissors and crumpling it up. The FBI was able, through a rather elaborate process, to reassemble that disk and retrieve the incriminating information from it. (Interestingly, he smuggled a pair of scissors into the interrogation room and the cops handed him the actual disc - and that's when he cut it up, right in front of them. How embarrassing.) CD-R is not far behind for the FBI, most likely, so leave the details of your transgressions in your head, not on a disc.

So, for the paranoid, or those whose data is truly sensitive or secret, we can move on to other levels of destruction. One effective, but not necessarily recommended, method of destroying data on a compact disc is to zap the disc in a microwave oven. It takes only a second or two to render the disc useless, as demonstrated here.

However, this method is not recommended for the general public, because it may damage the microwave, and it is unknown whether the byproducts of the meltdown may remain in the oven and subsequently contaminate any food cooked in it.

Destroying the reflective layer is effective and all too easy, as any of us who have tried to remove a sticky label from a CD well know. The reflective layer is thin and delicate. To demonstrate this, place a piece of duct tape across the top printed portion of a disc and pull it off with a quick jerk. Now you have gold- or silver-colored duct tape, and a semi-clear piece of polycarbonate. However, even if you remove all of the reflective layer, it is likely that the spooks at Langley or the sleuths in the Hoover Building could still find a way to replace the reflective layer and read data from the disc.

If you are not really concerned with security, but just want to quickly make a disc unreadable by the average person, you can destroy sector 16 of the disc. Sector 16 contains the disc's volume descriptor, and is necessary for any CD-ROM drive to be able to read the disc. How do you determine exactly where sector 16 is? Well, if you imagine the structure of the disc, you can get a good idea. Since a disc has approximately 333,000 sectors, usually a few more, but never less, and these begin at the center of the disc and move outward, sector 16 is pretty close to the center of the disc, within an eighth of an inch of the beginning of the writable area. Just take a car key or other sharp object and scratch a quarter-inch line across the beginning of the disc, on either side, or both. Now, with sector 16 unreadable, the disc is unreadable under normal circumstances, although the remaining data is still intact.

It's a little harder to destroy a pressed CD completely. Since the data, as represented by the transitions between the pits and lands on the disc, is physically stamped into the polycarbonate, removing the reflective layer still leaves the pits and lands intact. The only way to truly render a pressed CD useless is to remove the pits and lands physically from the polycarbonate. While you can buy a special CD destruction device for about $6,000 (hand operated) and the motorized version for about $11,000, the budget-conscious among us will surely opt for a cheaper solution. There are a couple of quick ways to make a pressed CD, or a CD-R for that matter, useless. Take it out to the sidewalk and throw it data side down; put your foot on top of it and rub it around for a bit. That will do the trick for most purposes. Tossing it on a belt sander has the same effect, but watch your fingers.

Sometimes we have enough trouble making CDs that it's hard to imagine wanting to destroying the results of our hard work. But there are times when data needs to be destroyed, and the methods mentioned here are only a few of the many ways to intentionally ruin a CD. Remember that there is a difference between making a disc unreadable and completely removing the data. Use the method that is appropriate for your own security purposes. Think a little and you will come up with some intriguing methods of your own. But remember: safety first!

Bob Starrett can be reached at http://www.cdpage.com

Bob Starrett's article on "How to Destroy a CD" prompted many additional suggestions, which are reprinted here with their authors' permission.

From: Michael Jennings

1. Put the CD-R between the pages of a newspaper, with at least 30 pages on each side. (This prevents anyone's being hurt by sharp or flying pieces.)
2. Bend until the CD-R breaks.

Anonymous:

I have found that obsolete CDs make excellent targets for "plinking" [target practice], which renders them fairly unusable. But for the "I don't ever want this read by anyone" CDs, the office shredder works very well!

From: Mark Poppin

The easiest and most effective way to destroy a CD completely is to put it into a plastic bag, wrap it further in newspaper and pulverize it with a hammer on a concrete floor. Here, you have safety and efficiency (unless you hit your finger with the hammer). The resulting polycarbonate dust and CD shards would be impossible to reconstruct.

From: Sean Bashaw

One of the solutions for destroying discs was to cut them in half. But the author stated that some highly skilled people could put the pieces back together and retrieve the data. That is true if they could get all of the pieces. I suggest doing what I do with my old credit cards. I cut them in half and throw away the half in two completely separate trash systems. Usually, I put one half in my home garbage and the other half in a dumpster at work. For CD-Rs I would suggest quarters, and toss the quarters into four different trash bins. Maybe one at the coffee place on the way to work, one at the grocery store, you get the idea.

From: jrconner

I'm surprised you didn't mention incinerating the CD with a propane torch or an oxygen-acetylene torch. It's not too dangerous an operation provided you wear protective gear, keep a fire extinguisher handy, and don't try it on the 20th floor of an office building.

...though I must admit that blowtorching a CD pales in drama and humor compared to zapping it on a Tesla coil.

From: Robert C McKenzie

With regards to CD destruction:

I have found that a minute in front of a butane torch does wonders in total destruction.

I have found that the "New and improved version 4.0" CD's may be made into a great plant holder and/or a concave mirror assembly for sun power, by using a bowl and hot water with a heavy weight placed on the center of the CD.

Love your methods, too.

From: Bob Rogers

I posted this question to the list a couple of months ago, and the one procedure that was suggested the most was to use sandpaper. Actually this is the procedure that I opted for and it has proven to be the easiest to use and hopefully meets my requirements just to keep the average person from reading my personal data.

Deirdre' says: And what about recycling them? Here's a suggestion:

From: Jcmaigrot

You did not mention an "ecological" use of old CDRs: hang them in your fruit trees (cherry, peach, etc.) to scare off the birds

Some of these discarded CDR have a GOLD layer on them; and I observe that:

1. they are the most light-resistant;
2. the golden-CDR seems to be the best bird-repellent; I know this because my bamboo grove is the dormitory for a great number of "pillards" (thief) and noisy black birds (in french, these birds are called "etourneaux");
3. However, my CDR-burner (an old 2X RICOH MP6200S) is so reliable, with EasyCD Creator V3.5c, that I have no more CDRs to discard !

This is the newsletter topic that refuses to die. Some of these ideas are just too creative (and too funny) to go into recycle bin. I've had lots more suggestions on recycling/reusing CDs as well, which will be covered in yet another (quite silly) article.

The original article mentioned several simple ways to make a CD unreadable by ordinary people, but also explained how to destroy a CD so thoroughly that even a law-enforcement agency would not be able to reconstruct it. This doesn't mean that we expect that our readers need to evade the law! But, in this day and age, anyone who keeps personal data on electronic media may have legitimate and well-founded concerns about privacy and data security, and it's a good idea to know how to protect your personal information from abuse.

From: Bob Hornberg, TX

I place an unwanted CD disk label side downward on the concrete end of my driveway, then vigorously rub the disc over the textured surface. The flakes of colored storage media are beautiful to behold, reflective at night, and last for quite some time before the elements remove them. And, you can still use the disc as a Frisbee.

From: Steve Brown gr8m8s@lvcm.com

I worked for a federal agency producing classified CDs for about three years so I'd like to comment about a few of the destruction methods in your latest article.

First, the burning methods are dangerous because of the toxic fumes put off by the plastic as it burns. This is not only dangerous to the person burning the CD, but it also pollutes the air everyone breathes. If a business or government agency is involved in the burning of CDs, they can be fined by the EPA.

Second, bending until breakage is a good way to shatter a CD that you don't want the average person to reconstruct, but it is in no way secure from the abilities of the NSA, CIA, FBI, and other government agencies to extract data from the bits and pieces. The NSA has issued guidelines for the proper destruction of CDs that renders the CD useless to even the techno-geeks at NSA. It amounts to sanding off of the top surface of the CD into pieces 1 micron or smaller (It's been a while since I read the spec, but I'm pretty sure that's correct). There are commercial vendors who make machines to do this for the rapid destruction of many CDs. Some are powered and some are not, but they are not cost-effective for the occasional user.

The easiest, safest, and most secure method to destroy a CD by hand is to sand off the top surface with a sanding block and fine sandpaper until you get to the clear part of the CD. The next most secure is to shatter it, but remember that most of the data can be reconstructed. CDs use an amazing error correction scheme on a micro-fine medium that makes even small pieces vulnerable to high-tech retrieval. It's always a matter of cost: if the data is worth a lot, a lot can be spent to retrieve it.

From: Pete Masterson http://www.aeonix.com

Heck, you missed the most obvious way to destroy a CD. Just give it to the USPS. I get CDs from AOL and with a couple of magazines... the Postal Service manages to get them into my P.O. Box usually by breaking them into 50 or more pieces. Very effective.

From: Ian Mander ianman@i.am

I work at a laboratory where we fire-test construction materials. We've had our main furnace up to 1156 degrees C (2113 degrees F), at which temperature polycarbonate CDs don't really stand a snowflake's chance in ...

From: Anonymous

Camouflage technique: Make your own AOL label and affix it to the top of your CD. No one bothers to look at it twice.....

From: Jim Kirkpatrick

When I've saved enough of them, I plan to put them on a rocket and launch it into space so that they'll burn up when they reach the sun. In case of a defective launch, the rocket explosion will destroy them. If sun orbit is not achieved they'll either burn up when they re-enter the earth's atmosphere or become lost in space for long enough that it won't matter if they are found because by then there probably won't be any hardware to read them. Foolproof plan, don't you think?

From: Michael Malone msm@flash.net

Well I haven't had the need to totally destroy a CD yet (I do a pretty good job of that without any difficulty). However, if I ever felt the need, I have the perfect solution. My two and a half year old nephew is a natural. Many people seemed concerned about safety. Well, that is not a concern with this solution. A souped-up diamond chain saw wouldn't stand a chance with this little guy. Just leave it on a coffee table in the same room with him and ten minutes later a mystic couldn't find a trace of anything usable.