So, you want to donate or recycle that old computer that’s been sitting in your storage closet for a while, but you’re concerned about the personal data on the device winding up in the wrong hands. You have reason to worry: Some people think that simply deleting files and programs completely removes that data from their computers. It doesn’t.


However, there are steps you can take to dramatically and, in one case at least, completely eliminate the risk of someone else accessing your data after your computer’s been donated. Follow these tips on how to wipe your computer clean before recycling it.  


Hanging Around

The U.S. Environmental Protection Agency (EPA) compares merely deleting a computer file to getting rid of a card from a library’s card catalog but not taking the corresponding book off the shelf. “The information is still in the library if you look for it,” the agency says in a brochure on its “Plug-In To e-Cycling” website.


Similarly, deleting a file removes information about its location from a hard drive’s index but leaves traces of the data behind, which renders the information readily accessible to someone armed with data recovery software, EPA says. 


Reformat and Reinstall

One way to reduce access to your data is to reformat your hard drive using a start disk, also called a boot disk, and then reinstall your operating system. Older computers often came with a start disk; with more recent models, you may be able to create one using your computer or download one from the manufacturer’s website. For specific instructions on how to reformat and reinstall on a computer running Windows, read this article by Kim Komando, host of a nationally syndicated radio show on computers. For tips on how to reformat on a Mac, consult your owner’s manual. 


“Reformatting will keep most people out of your old files,” Komando writes. “But specialized software exists to reclaim files after reformatting. If you do not know who will get the computer – or you do know and you don’t trust them – stronger measures are required.”


Overwriting Software

One stronger measure is the use of software designed to wipe away the data on your hard drive. Such programs overwrite your files with “nonsense data,” according to computer recycling tips complied by the Western Lake Superior Sanitary District (WLSS) in Duluth, Minn. This kind of software is available for purchase or free downloads. WLSS recommends typing “hard drive scrubbing software” into your search engine to find a program that’s right for you. You can also turn to pages 2 and 3 of this EPA brochure to see a list of overwriting software for both Window operating systems and Macs.


Both Komando and WLSS recommend running this software overnight, as it can take many hours to perform its tasks.


Bring the Hammer Down

In the end, “the only absolute and assured way of protecting your data is to destroy the hard drive,” Komando writes. To do so, remove the hard drive from your computer and then use a hammer or drill to destroy the drive’s disc platters. For a comprehensive overview on how to do this, watch this instructional video from Best Buy’s Geek Squad.


Ultimately, Komando recommends using the overwriting software. Physically destroying the hard drive “seems excessive to me,” she writes. “But you’re right to be paranoid about this. Identity theft has become overwhelming … I believe in being careful, no matter who gets the computer.”


By taking the steps above, you too can be careful and reduce the risks of your personal data falling into the wrong hands.


Have other tips for wiping your hard drive? Leave us a note in the comments below.