I have once used CCleaner to "Wipe free space" in the advanced option. It took quite a long time. I have noticed, in the "Options", "Settings" you can set a secure deletion for 1 pass, 3 passes, 7 passes or even "Gutman" at 35 passes. This seems a very good free facilty if needed, but is it too long winded and do other programmes work better? This may be worht a thought ig you were selling or giving the PC to someone else, or would the data still be recoverable? eg Emptied recycle bin after deeting data files.
This topic is riddled with myths, urban legends, and misinformation. The authors of CCleaner either don't know what they are doing or intentionally perpetuate these bad ideas for marketing purposes. The article <a href="click here">"Shred files and wipe disks"</a> should set the story straight. If you are giving a PC to someone else, it may be possible to recover useful information if you simply delete files, empty the recycle bin, and wipe the free space because some information will be slack space (very small, not usually significant), swap memory, hibernation file, Windows registry, and application (e.g., Firefox) registries. Also, multiple passes are completely useless and redundant.