Mac OS X has a built-in way to permanently delete files and folders.  No additional software is required.

Warning: This process will irrecoverably delete all files in your Trash folder. Once the Trash has been securely deleted, all files and folders that were in the Trash CANNOT BE RECOVERED.  Before using Secure Deletion, be sure that the files and folders in the Trash will no longer be needed.

System Requirements

OS X v.10.4 or higher

How to securely delete a file or folder:

  1. Drag the files or folders you wish to securely delete to the Trash, located at the far right of the Dock.
  2. Click once on the Trash icon to open the Trash folder and make sure you are ok with permanently deleting all files and folders in the Trash.
  3. From the menubar, choose Finder > Secure Empty Trash .
  4. You will see a warning message alerting you that the files will be deleted.  Click OK to start the secure deletion process.
  5. NOTE: The Secure Emprty Trash process takes slightly longer than a normal emptying of the Trash because the files and folders are overwritten seven times to make them unrecoverable.
  6. Once the progress bar disappears, all files and folders that were in the Trash are now gone for good and completely irrecoverable.