Which files can I safely delete?
Unfortunately there is no short and easy answer to this question because usually one cannot know where a file came from and what it is used for. Generally temporary files and cache files of the internet browsers can nearly always be deleted safely. Besides deleting files, the File Search of the software offers you to move files to a different drive or to a compressed ZIP file (preserving the file system hierarchy) which can then be archived. That way files that are still needed can be easily restored, either manually or by using the restore script that the software is able to generate optionally.