Refurbish Computer: Intro to Digital Data Removal

Refurbish Computer

Introduction to Digital Data Removal



In 2003, two graduate students at MIT’s Laboratory for Computer Science bought 158 used hard disks on eBay and other places. From those hard disks, they were able to discover 5,000 credit card numbers, personal and corporate financial records, medical records and personal e-mails. Only 12 of the 158 hard disks had been properly cleaned of their data. Approximately 60% of the hard disks had been reformatted, and about 45% of the disks had no files on them (the disks couldn’t even be mounted on a computer) – yet the students were still able to recover data from them, using a variety of special tools.1




A modest computer may open a new world for someone lacking access to digital technology. A center for assistive technology reutilization (ATR) has a tremendous incentive to capture for re-use the many computers that are being discarded as owners acquire newer equipment. But, it is very important to remove all data from the hard disk to guard against identity theft and fraud. As noted in the incident above, information in resumes, credit card information, Social Security numbers, and passwords to web sites may exist on disks that appear to be clean.


After acquiring computers for re-use, the first priority should be to physically clean and sanitize the equipment to prevent the transmission of disease2 and the second to clean and sanitize the hard disk – using software, not chemical cleaners – to remove confidential, secure or proprietary information. Each center should adopt a standard process and acquire the software tools to accomplish this goal.


Data destruction should take place upon receipt of donated equipment to ensure that information remaining on the hard disk cannot be used in ways that harm the donor or others. The standard process should be used with all hard disks, even if no documents appear to be stored. The process may be time consuming, depending on the size of the hard disk, the type of software used for removal and the process chosen. Adequate time should be scheduled to accomplish this task before making the computer available to a new user.


Guideline for Acceptance of Computers


The ATR center should establish criteria for the types of computers to be refurbished. A reasonable guideline is that computers intended for reutilization in this country should be no more than five years old. The reason for this recommendation is that reconfiguring pre-Pentium computers to run today’s software can cost as much as $400 each.3 That begins to approach the cost of acquiring new low-end machines. Older machines can be sent to a commercial recycler where useful components will be salvaged before disposing of the remainder in an environmentally responsible manner.


Donors should be encouraged to include software, manuals and documentation that came with the computer. The center should have a procedure for labeling all components of the computer and related documentation with a common number for identification of related items.


Facility, Tools and Staff


The assistive technology reutilization center should have a designated area for working with donated computers. This area should be a secure room with adequate work space, power for a large number of electric outlets, good lighting and work tables for the computers. It should have a computer with Internet access for the technician, but Internet access is not needed to perform data removal.


Data removal is performed with disk wiping software. One large refurbisher, Computers for Classrooms, Inc., in Chico, California, recommends Paragon Disk Wiper and Blancco. Both products wipe the disk using a process compliant with the DOD standards described earlier. Other disk wiping software options are listed in the document, Software Programs for Data Removal.  If the center has large volumes of donated computers to process, a KVM switch box can be used to wipe up to eight hard disks simultaneously.


A certified technician is not essential, but the person performing the disk wiping should be computer savvy and well trained in this procedure. This task must be performed at the appropriate point in a carefully planned workflow for processing donated computers. Complete removal of data from disk storage devices requires an understanding of how the data is stored on computer media. which is explained in Refurbish Computer: Removing Data from Hard Drives.




1 “Remembrance of Data Passed: A Study of Disk Sanitization Practices.” Cambridge, Mass.: Massachusetts Institute of Technology, 2003. (

2 See separate module, Cleaning Computers, Keyboards and Mice.

3 Lynch, Jim, “Ten Tips for Donating a Computer.” Retrieved February 7, 2008, from centr/hardware/page5496.cfm




Please note that by selecting an Internet link you will be directed to an external site, and the Pass It on Center does not control the content of the site.



This work is supported under a five-year cooperative agreement # H235V060016 awarded by the U.S. Department of Education, Office of Special Education and Rehabilitative Services, and is administered by the Pass It On Center of the Georgia Department of Labor – Tools for Life.  However, the contents of this publication do not necessarily represent the policy or opinions of the Department of Education, or the Georgia Department of Labor, and you should not assume endorsements of this document by the Federal government or the Georgia Department of Labor.


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Other Information

Title: Refurbish Computer: Intro to Digital Data Removal
Module: Program Operations
Author: Trish Redmon
Audience: Implementer
Sub Title:
Procedure: Wiping hard drives
Organization Source: Pass It On Center
Last Reviewed: 10-25-2009 5:30 PM