You have a pile of DVDs with sensitive information on them and you need to safely and effectively dispose of them so no data recovery is possible. What’s the most safe and efficient way to get the job done?

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The Question

SuperUser reader HaLaBi wants to know how he can safely destroy CDs and DVDs with personal data on them:

I have old CDs/DVDs which have some backups, these backups have some work and personal files. I always had problems when I needed to physically destroy them to make sure no one will reuse them.

Breaking them is dangerous, pieces could fly fast and may cause harm. Scratching them badly is what I always do but it takes long time and I managed to read some of the data in the scratched CDs/DVDs.

What’s the way to physically destroy a CD/DVD safely?

How should he approach the problem?

The Answer

SuperUser contributor Journeyman Geek offers a practical solution coupled with a slightly mad-scientist solution:

The proper way is to get yourself a shredder that also handles cds – look online for cd shredders. This is the right option if you end up doing this routinely.

I don’t do this very often – For small scale destruction I favour a pair of tin snips – they have enough force to cut through a cd, yet are blunt enough to cause small cracks along the sheer line. Kitchen shears with one serrated side work well too. You want to damage the data layer along with shearing along the plastic, and these work magnificently. Do it in a bag, cause this generates sparkly bits.

There’s also the fun, and probably dangerous way – find yourself an old microwave, and microwave them. I would suggest doing this in a well ventilated area of course, and not using your mother’s good microwave. There’s a lot of videos of this on YouTube – such as this (who’s done this in a kitchen… and using his mom’s microwave). This results in a very much destroyed cd in every respect. If I was an evil hacker mastermind, this is what I’d do. The other options are better for the rest of us.

Another contributor, Keltari, notes that the only safe (and DoD approved) way to dispose of data is total destruction:

The answer by Journeyman Geek is good enough for almost everything. But oddly, that common phrase “Good enough for government work” does not apply – depending on which part of the government.

It is technically possible to recover data from shredded/broken/etc CDs and DVDs. If you have a microscope handy, put the disc in it and you can see the pits. The disc can be reassembled and the data can be reconstructed — minus the data that was physically destroyed.

So why not just pulverize the disc into dust? Or burn it to a crisp? While technically, that would completely eliminate the data, it leaves no record of the disc having existed. And in some places, like DoD and other secure facilities, the data needs to be destroyed, but the disc needs to exist. If there is a security audit, the disc can be pulled to show it has been destroyed.

So how can a disc exist, yet be destroyed? Well, the most common method is grinding the disc down to destroy the data, yet keep the label surface of the disc intact. Basically, it’s no different than using sandpaper on the writable side, till the data is gone.

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