NIST Special Publication 800-88
This product ensure your organization is meeting the standard put forth in the NIST 800-88, 800-36 Guidelines for Computer Security.
"Clearing information is a level of media sanitization that would protect the confidentiality of information against a robust keyboard attack. Simple deletion of items would not suffice for clearing. Clearing must not allow information to be retrieved by data, disk, or file recove ry utilities. It must be resistant to keystroke recovery attempts executed from standard input devices and from data scavenging tools. For example, overwriting is an acceptable method for clearing media".
NIST Special Publication 800-36
"Overwriting. One method to sanitize media is to use software or hardware products to overwrite storage space on the media with nonsensitive data. This process may include overwriting not only the logical storage location of a file(s) (e.g., file allocation table) to be erased or permanently removed but also the entire media, including all addressable locations. The security goal of the overwriting process is to replace sensitive data with nonsensitive random data. Media should be overwritten a minimum of three times using a method based on the information sensitivity contained on the media. Overwriting cannot be used for media that are damaged or not rewritable. The media type and size may also influence whether overwriting is a suitable sanitization method".