Recycling old and unwanted computer systems is good for the environment. However, before you take that old computer to the recycling center or ship it back to the manufacturer, it is your responsibility to ensure you are not also inadvertently giving away your personal information. Computers can collect and store information related to daily use, such as usernames, passwords, credit card numbers, bank account information, confidential emails and website sales receipts. Computers are also excellent at storing seldom used documents, such as tax returns, medical records and resumes. If you do not adequately remove your personal information prior to disposing of your computer, there may be unintended consequences, including identity theft, financial loss and/or embarrassment.

Simply reformatting the hard drive or deleting files does not permanently erase the information stored on the drive. The next person who takes possession of your computer could use a relatively simple and free software package to recover data you thought you erased. The two methods for removing information from a hard drives are overwriting and physical destruction.

Overwriting data: Replacing previously stored data on a drive or disk with a predetermined pattern of meaningless information, such as a string of 1s or 0s on every part of the drive or disk. The overwriting process should make at least one pass over the entire drive to reduce the chance that personal or financial data could be recovered. Additional passes will further reduce the potential for data recovery, although a single pass will defeat most software recovery attempts. The Microsoft Windows XP installation CD, Microsoft Windows Vista installation DVD and the Apple OS-X Installation DVD contain disk management tools that can be used to overwrite the data on drives.

The following software programs can also be used to overwrite the information on the hard drive:

• ActiveDisk 
• Active@KillDisk  
• DBAN "Darik's Boot and Nuke"  
• DriveCleanser  

Physical Destruction: Physical destruction can be used to prevent the recovery of personal or financial information from defective or obsolete hard drives. The goal with physical destruction is to damage the hard drive disk platters. To perform physical destruction, remove the hard drive from the computer and disconnect any cables or mounting brackets. Drilling multiple holes into the hard disk platters will preclude use of the hard drive and provide reasonable protection from recovery of the data written on the drive. The hard drive can also be subjected to physical force by pounding with a large hammer that will disfigure, bend, mangle or otherwise mutilate the hard drive so it cannot be reinserted into a functioning computer. If you choose physical destruction as the method for reducing the risk that your personal or financial data could be recovered, please be careful and be sure to wear safety equipment, like goggles and gloves.

Ask the recycling or collection vendor, or the manufacturer, about recommended security precautions.