Use disk shredding tools before passing on a hard drive that may contain sensitive information. As with file shredders, you'll find plenty of commercial utilities that can accomplish this task, but capable free ones exist as well.
Look to the popular Darik's Boot and Nuke (http://dban.sourceforge.net), for instance. This programme runs from a boot disk or drive and proceeds to securely erase any hard drive that it finds on a system.
Courtesy: IANS
