When you format a hard drive you don't actually erase the hard drive of data, you only erase the location information for the data, making it "lost" to the operating system. Since the operating system can't see the data, the drive looks empty when you look at its contents.

Erasing a hard drive completely is not as easy as deleting everything on it. To truly erase hard drive data forever, you'll have to take some extra steps.

1. Use a Degausser to Erase the Hard Drive
Use a degausser to disrupt the magnetic domains on the drive - the very way that a hard drive stores data.

Some NSA approved automatic degaussers can erase dozens of hard drives in an hour and cost thousands of dollars. NSA approved degaussing wands, used to manually degauss a hard drive, can be purchased for around $500 USD.

Important: Degaussing a modern hard drive will also erase the drive's firmware, rendering the drive completely useless. If you want to erase a hard drive, but also want it to work properly after being erased, Then I recommend you to erase the drive using data destruction software instead.

Note: For the average computer owner or organization, degaussing probably isn't a cost effective way to completely erase a hard drive. In most cases, physically destroying the drive is the best solution if the drive isn't needed any more. - See more at: http://trendymediablog.com/2014/09/how-to-completely-erase-a-hard-drive/

Gonna try it wen I get Τ̅Ơ̴̴̴̴͡ workshop