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Comment by spindritf | Hacker News Reader

> if you're using optical media, those disks will be impossible to erase

I pop the old optical disks I'm tossing away into a microwave oven for 10 seconds at 1000 watts. How recoverable is the data stored on them? (And how cancerogenus the stench?)

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When microwaving a CD, the induction stops when the track is cut. There are usually big chunks of surface (~2cm²) unaffected. You can't read it with your drive but it's reasonable to think that some data can be retrieved from it, with enough work and money.

A belt sander with rough grit should take care of that without damage to device or surroundings. Sand from the top -- that's where the data is, or used to be. For paranoid satisfaction, sand it all the way through.

It seems like the simplest way would be to burn it.

I'd like to suggest to everyone trying this that: 1. holding such a thin object against a belt sander may be difficult. 2. if you lose your grip, it might fly across the room at dangerous speed.

In the same spirit, I'd like to suggest that anyone trying this use some sort of jig to hold the disc against the belt rather then try to hold it in place against lateral force with your bare fingers.

Source: long-ago experience. Ouch.

More than you would like. The amount of surface area left is substantial so something could be recovered. The best way is to melt them with thermite. If it is legal in your area.

wait, thermite is illegal?

I have no idea. Chances of a mix that violently burns at 1300 degrees being under regulation somewhere in the wide world are not that slim.

It's useful for fixing cracks in cast iron and joining rails, so I don't see why it'd be regulated.

Something being regulated does not mean that it can't be used industrially. Many types of explosives are regulated even though they are used industrially every day in quarries and mines.

Still, restricting thermite would be silly and ineffective. As a chem-lab assistant, I made the stuff in highschool. Aluminum powder is widely available and rather cheap, as is iron oxide (obviously ;). I also made cupric oxide thermite, but that didn't work as well.

Everything fun is illegal somewhere.

Apparently the dye coating used on CD-Rs [0] has a melting point of 200-300C [1]. This is enough that even a candle would melt [2].

[0] http://en.wikipedia.org/wiki/CD-R

[1] http://www.tstchem.com/eng/?page_id=243

[2] http://en.wikipedia.org/wiki/Fire#Typical_temperatures_of_fi...

(Links to more scientific evidence appreciated)

Well, CDs contain BPA for one. If you enjoy endocrine disruption, this could be your easy ticket!

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