Does anyone know an easy, work friendly way to destroy CD-Rs?
I use CD-Rs at work frequently to back up large data files. Once I make a new CD-R of the data I don’t really need the old one anymore. The data is confidential, but not “top-secret-if-I-tell-you-I-have-to-kill-you” stuff. For various reasons we don’t use re-writeables, but even if we did I will still be stuck with a stack of them I need to get rid of.
Here are the things I have tried
Cutting them with scissors. It seemed dangerous (I don’t want to lose a finger) and messy. Also, with my old scissors they were pretty hard to cut.
Burning the with a lighter. Smells bad! Plus I am worried about the smoke detectors.
I don’t want to use a magnet because I don’t know how to prove that the data is completely destroyed.
What should I do? Is there a program that deletes them? If I colored on the back with a “Sharpie” marker is it destroyed?
Very bright sunlight can do the trick. Leave them in the sun or better yet use a magnifying glass.
Okay, more seriously. The data is on the “top” of the CD. Use the edge of something sharp like scissors and scrape off some of the top coating. Make sure you can see thru it. Make a wide line from the center to the edge.
If was really sensitive data, all of the material needs to be removed. Breaking the CD would be a good idea too.
The data is actually burned into an emulsion or metallic film layer sandwiched between two layers of plastic. I seriously doubt you could scrape deeply enough to reach the actual data.
What you can do is seriously scratch up the bottom side of the disc to the point that it scatters the laser beam as it tries to read the data (the top is where the label is and the laser can’t read that side).
Keep in mind, CDs are an optical media which use “pits and flats” to represent the 0’s and 1’s necessary for digital communication. A flat reflects the laser beam, while a pit absorbs or scatters it. These things are packed rather closely together and anything that interferes with the reading laser getting a clear view will cause problems.
That said, scratches on the bottom of the disc work well. A good, dark black, permanent marker scribbled on the bottom will also do a fair job of making the disc unreadable.
CD-R’s do use a heat-sensitive film or emulsion to record the data which is burned into it by the laser of the CD writer. I would guess that heating the disc sufficiently would cause the emulsion to go black and become one giant “pit”, rendering the data unreadable, but I have no idea how hot you have to get it to achieve unreadability. Perhaps some experimentation is in order.
Personally, I use a little bit of sandpaper and a black Sharpie on the bottom of the disc and don’t worry too much about it.
The data is on top and can be very easily be scratched. There does not appear to be a layer of plastic over it (but some older audio cd’s do appear to have a protective layer).
You can test it out very easily with a screwdriver and a aol disk.
The data, as in the binary encoded information, is on the bottom side of the emulsion layer and is read by a laser shooting up from below. It does appear that some of the less expensive CDR’s do dispense with the upper layer of plastic thereby making it possible to scrape away the film that the data is burned into. If you are using that variety of CDR, then removing any labels and scraping away the metallic film will indeed render the CD unreadable. Otherwise you’ll need to use some of the methods described above.
While the OP is not concerned about maximum security, just scratching the bottom is not enough. The bottom can be made smooth with polishing and/or filler. Ditto marking the bottom with pens. Note that CD-R makers recommend using “oil-free” pens to write on the top. Ergo, get some nasty oil-based solvent …
Can somebody please tell me how microwaving a CD for a few seconds could damage the oven? I’ve used this method to fry discs, and you get cool “vein” patterns etched into the metallic layer, and no damage to the microwave AFAIK.
I don’t have details on this, but microwaves were designed so that the microwave energy broadcast into the cooking chamber would be absorbed by the water molecules of what you’re cooking. If you run it ‘dry’ without anything with moisture content in the microwave, that energy has to go somewhere else.
There’s an easy fix though: put a microwave-safe glass of water in there whenever you fry your CDs.
There’s another way that the CD could damage the microwave: excesive microwaving can cause the disc to catch fire. Even with minimal microwaving of 3-5 seconds, there’s a little bit of smoke and vapor released from the cooked disc. Frying CDs in bulk could deposit whatever chemicals are in that smoke as a film on the inside of your microwave.
What I’m getting at, is that if you’re going to use this as a method of bulk CD disposal, use a cheap microwave that you bought specifically for the purpose, and not the one you regularly use for food preperation. And keep a fire extinguisher handy.
There is a company called Pressit who market a cd destroyer.
It’s a bit like one of those cd cleaners you see, exept with this one you put the cd in, put the lid on and twist a few times, and it covers the cd in lots of circular scratches.
UK price about £8 or£9
