One of the options thats a tad bit hidden in OS X is the Secure Erase option, which runs a multi-pass erase on a volume. Additionally, there’s no option to Secure Erase free space on a volume. But you can still securely erase whatever you’d like (other than you boot volume obviously), when needed. To do so, use the diskutil command along with the secureErase option. The format of the command to secureErase freespace is: diskutil secureErase freespace [level] [device] The levels are as follows (per the man page as not all of these are specified in Disk Utility): Single-pass zero-fill erase Single-pass random-fill erase US DoD 7-pass secure erase…