New
#11
The only really secure way to clean HDD/SSD is invokimg ATA Secure Erase command. Linux commandline utility hdparm can be used to do this; however, it isn't user friendly at all. PartedMagic live distro has graphical tool to do it, but it isn't freely distributed anymore, at least the official way.
SSD vendors usually offer their own tools (Intel SSD Toolbox, Samsung Magician, OCZ SSD Guru...) but their Secure Erase function is locked to SSDs of the same brand.