As an advanced option in CCleaner, it would be useful to be able to overwrite unused hard drive space using CCleaner.
Eraser, has this functionality and I think it would fit nicely into CCleaner (or even Recuva) as an advanced option in perhaps a separate button from the main cleaning options. Once this has run, Recuva should not to be able to find any files to recover.
It would be very useful for making sure sensitive files are definitely overridden, including ones than get deleted via [shift]+[delete] by-passing the recycle bin and hence not being shredded by CCleaner.
elyoh