How do you run CCleaner on another hard drive like an external or just any other drive other than the one with the OS on it?
CCleaner on C:drive only only get temp on C:Only all you need
It's true that the temp files cleanup facility is not relevant or available on other than your system drive, but you can add files to be deleted (and overwritten if you wish) from another drive by including these in the Include option. Use the Add Folder/Add file button and select the folder/file you want to delete, then click on open, which will add the folder/file to the include list.