How to destroy a hard drive with bleach

Trying to destroy a hard drive using bleach

As a datahoarder I am constantly buying new hard drives and consolidating the contents of old ones. I personally wipe the old drives in software and then donate them to a local charity for them to sell. I’ve noticed in the datahoarding community that a lot of people are in the same position and seek advice on how to destroy their old drives. Over the past couple of months, I have noticed people asking if they can destroy their old hard drive using bleach. I find this such as odd question because it’s not possible to destroy a hard drive using household bleach. Where on earth did the strange notion that bleach somehow destroys digital data come from?

Bleach tends not to destroy metal, at least not more than many other liquids would. I have two theories as to why people are becoming confused thinking that perhaps bleach destroys hard drives:

BleachBit and Hilary Clinton’s hard drive

If you cast your mind back to around the US 2016 presidential campaign, there was a scandal involving Hilary Clinton and her private server. The accusation was that Clinton had been using a private non-secure server for official government business and email correspondence. This is, of course, a big no-no and was seen as very damaging to her politically. It was widely reported following an FBI investigation that Clinton’s staff had used BleachBit to wipe the hard drive of her mail server. BleachBit isn’t new, it’s a software application that’s been around since 2008. The software can be used to securely wipe both files and free space from hard drives. Not many non-technical people had heard of BleachBit at the time, so it isn’t hard to imagine that they were getting BleachBit and standard bleach (such as sodium hypochlorite) mixed up. It’s also possible that people understood from the media, at the time, that it was a software application but as time has passed, they’re simply remembering the word “bleach”.

Bleach is a common household item

My second theory is that when people need to “clean” their hard drives, they start looking around their homes for something suitable. For most people, bleach is possibly the strongest cleaning solution they have in their homes. Imagine you were about to take your old computer to the Good Will and remembered that your old tax records were still on the hard drive. You’re standing in your kitchen looking around and see the bottle of Clorox or Domestos. You might grab your phone and post online asking if it’ll destroy your hard drive. It’s a bit of a stretch of the imagination but again, I can’t fathom how anyone would think that using bleach to destroy their data would be feasible.

Alternative to using bleach to destroy hard drive data

Now that we’ve established that using bleach isn’t an option, let’s move onto some more sensible suggestions to either wipe your old hard drive or even destroy it.

1) Securely wiping the drive using software

If the hard drive is still working and can be attached to your computer, wiping it using software is by far the best solution. The benefit of this is that the drive can then be given away or donated and can still be used by someone else. I think people are worried about taking this approach after seeing in Movies and on the news that data can still be recovered. If you were to just casually select your files in Windows and hit delete, then, of course, it’s possible that a bad actor could at some point “undelete” or recover them. This is because when you delete files from within Windows (and Mac and Linux too), you’re not really removing the file’s data. All you are doing is letting the operating system know that you don’t care about these files anymore and that the space they occupy on the hard drive can be used by something else when needed.

For these reasons, you need to use a special software program to securely wipe your data. If possible, I would strongly recommend booting to a live or “offline” environment, This means that you’re going to run an operating system or data deletion tool, not from your hard drive, but from other media (such as a bootable USB, CD, DVD, Floppy, etc). This is necessary because if the system is currently running from the hard disk drive that you’re trying to wipe, it isn’t going to work. You won’t be able to wipe the drive because you’re using its contents to run your system. If the hard drive you’re trying to wipe is a second (or third, fourth, etc) drive, this is less of an issue and can be worked around.

For a long time, a tool called DBAN was my go-to recommendation, DBAN stands for “Darik’s Boot and Nuke” and as the name suggests, it’s a self-contained system that lets you boot your computer and wipe its drive. You would download DBAN as an ISO file and either burn a CD/DVD of it or create a bootable USB stick. Once created, you would boot your machine from the DBAN media, follow the instructions, and your drive would be wiped. It would take a little while as every sector of the drive would be over-written. Depending on the size of your hard drive and its controller/interface this could take anywhere from 30 minutes to 48 hours!.

Unfortunately, whilst writing this post, I headed over to DBAN’s website at https://dban.org and to my horror, discovered that they’ve been commercialised! I’ve not researched how this happened, perhaps the developer started a commercial venture or perhaps a company bought or registered the DBAN trademark. Anyway, the website clearly states that “DBAN is a registered trademark of Blancco Technology Group”. There’s a comparison matrix, comparing DBAN alongside Blancco’s commercial offering, something called ” Blancco Drive Eraser”. Of course, the website is trying to push you to pay for their commercial product rather than downloading the original DBAN for free. To be fair, I’ve not heard any complaints about DBAN recently so I will still recommend it as a viable option, I wouldn’t, however, risk paying for the commercial “Erasure” product. Even if DBAN isn’t what it used to be, it’s still better than trying to destroy your hard drive by using bleach ;).

2) Physically shredding the drive

This option is more for businesses as there is usually some cost involved. In my professional capacity, several times a year I have the need to destroy the contents of around 1000 hard drives. I approached a company advertising that they shred hard drives for 6GBP each (7.50 USD each, at the time of writing). True to their word, you need to have a requirement to destroy at least 50 hard drives (or in other words, be prepared to spend 300 GBP each time), and they will drive to your office/home/factory, etc and throw all of your drives into a shredder in front of you. The whole process is quite impressive to watch, turning the drives from heavy, robust, pieces of spinning metal into tiny fragments, a few mm in diameter. They even provide you with a written document listing the serial numbers of the drives and the destruction process they’ve undergone. If you have contracts stating that you must keep data secure, this will likely keep all stakeholders happy.

3) Taking a hammer to the hard drive

This is a step up from submerging the drive in bleach (which as we’ve established, will NOT destroy its contents) but isn’t as secure as wiping the drive in software or having it professionally shredded. Basically, as I’m sure you’ve guessed, you just place the hard drive on a flat surface and beat it with a hammer until the platters are exposed and in a million pieces. The platters will be either glass or steel depending on the drive’s form factor (laptop, desktop, etc). Of course, this is a heavy-handed method that has its drawbacks. One major downside is that the drive is completely destroyed, so it can’t be donated or re-purposed (like with shredding) yet also isn’t 100% fool-proof. If you are just worried about someone casually reading or recovering your data, this will do the job. If on the other hand you work for a large company or the government and have some trade-secrets you’re trying to destroy, this is a risky approach. It’s entirely possible that a cash-rich adversary could recover the drive’s fragments and reconstruct them. I would consult your organisation’s IT policies and also GDPR or similar before resorting to this old-fashioned method. Like I say, if you’re just trying to destroy your own personal hard drive after taking the PC to a charity shop then hammer away! It’s a million times better than trying to use bleach.

4) Drilling the drive.

This is probably the easiest, yet least secure data destruction method, assuming you have a drill to hand. The process is basically drilling a series of holes right through the drive. This will prevent the drive from spinning-up and also prevent someone from casually performing data recovered on the drive. If you’re taking your old computer to the rubbing tip (or “dump” for our American friends) and don’t want someone stealing your identity, this is a valid technique. Like the above “hammer” technique however, you should be aware that it isn’t completely safe and wouldn’t fulfill the majority of commercial contracts or laws on data destruction and privacy. At the risk of repeating myself, yes, it’s better than trying to use bleach to destroy the drive.

Summary

I hope I’ve explained why you shouldn’t try to use bleach to destroy the contents of an old hard drive, and provided you with a few alternatives. If you have any questions or comments, please leave them below. Enjoy your data-hoarding and don’t forget to support the good people over at archive.org.

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