I'm a regular user of Piriform's program, especially CCleaner. I love to use the wipe free space feature, but I have a question about it.
In the settings you can set the program to secure file delete with DoD, NSA and so on. But when CCleaner wipes, does it use the selected method or another?
please don't use the WFS unless you are selling the hard drive.
Wiping the drive with regularity will greatly reduce the lifetime of your drive; it does not add any performance benefits and frees no space.
All WFS does is take the space you are not currently using on the drive and destroy the traces of anything that once occupied the space.
I believe the consensus on the site is that WFS is not using the overpass technique (DOD, NSA, Gutman) though this (i believe) has not been confirmed or denied by the developers.