CCleaner won't securely delete files that have already been deleted (i.e., shft+delete deleted or simply emptied from the recycler). To securely delete these files, then, you have to use either Recuva or CCleaner's Wipe Free Space (and Wipe MFT Free Space if you want to have the file names wiped and renamed). Am I right?
Spot on.
However, if you have not yet deleted a file and want it securely deleted, wiped from MFT and renamed - you can do so by deleting it via CCleaner. Am I right? My question is then, do you do this by choosing the include alternative in options, or how do you do it?
When you run the Cleaner section of CC, with either the default settings or your own custom set of boxes checked, CC will delete a specific set of files, as shown in an Analyse run. If, prior to the Cleaner run, you go to Options/Settings and check Secure File Deletion, One Pass, Wipe Alternate Data Streams and Wipe Cluster Tips, then the Cleaner run will overwrite all the file data and file names in the MFT - for this specific set of files. (Secure File Deletion is a separate option from Wipe Free Space.)
If you want a file, or files, deleted that aren't included in CC's standard clean, then you can enter the path and file name in the Include section, and check the Custom Files and Folders box in Cleaner/Advanced.
Also, I'm not really sure what this is supposed to mean:
"CCleaner can only securely delete files which have not yet been deleted from the Recycle Bin. If you have already delete files insecurely (for example, using Windows Explorer), you can delete them securely using Recuva."
But if I run a wipe free space (with everything else checked, including the Secure file deletion (Slower) option) - won't these already deleted files become securely deleted. Or is that just a terminology thing - where these already deleted but not securely deleted files will become wiped?
This has caused confusion before. It means that CC will only securely delete live files and files in the recycyler (if you have that option checked). If you have done a shift/del, for instance, the file will not have been securely deleted and can't be using CC, as CC's Cleaner section only deletes live files and files in the recycler. Then you may use Recuva, which will not remove the file name from the MFT, as the operating system won't allow it to do so.
You can use CC Wipe Free Space to overwrite all the free space on the disk, and the MFT entries. This will overwrite (which is secure deletion) every deleted file on the disk. (Perhaps the quote from the docs was written before CC's Wipe Free Space was introduced.) Again, Secure File deletion and Wipe Free Space are separate processes.