If you have ever needed to erase data securely you may want to try MacCleanse.  MacCleanse securely scans your system and erases the data of your choosing. "Whether you have been gift shopping online, discussing confidential business matters, visiting inappropriate web sites, or just wanted to clean out your system."  MacCleanse also is careful to not destroy the important information like others with a brute force style of getting the job done.  

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