Custom Folders not being cleaned

I have set up 'Custom Folders' to be cleaned on several different machines(all XP Pro) using several different versions of CCleaner. Usually the newest at the time.

The folder(s) I'm trying to clean is C:\Documents and Settings\'User Name'\Local Settings\Temp.

CCleaner does not seem to be able to clean these folders. I have looked in these folders after running the program, but prior to setting up the custom folder, and found stuff in there, which is why I set it up in the first place. After setting it up and hitting 'run cleaner' the stuff is still there.

So I think maybe it will clean the folder(s) on reboot(obviously set to clean on boot). No luck.

Am I missing a step in the setup process?

Why aren't these folders cleaned by default? It seems like an obvious place to clean, to me.

These folders are cleaned by default. Options, Advanced, Only delete temp files older than 48 hours.

It may not be able to clean everything, as some of the files may still be in use.