The default options of Disk Cleaner are best. It will search system hard disk for invalid files and will show you in the list. You can at any time stop the search process by pressing the stop button.

After the search is complete Disk Cleaner will show you a complete list of files it has found. Then select the files from the list which are to be removed and press the delete button to get rid of them.

You can customize each and every aspect of Disk Cleaner from the search process till the deletion process.