Upload Directory Cleaner
Upload Directory Cleaner scans through your WordPress upload directory searching for all files not being registered in your Media Library. After the scan, choose which files to delete from the list showing all unregistered files.
Scan Directory (Settings: Exclude top-level directories and files from the scan or add custom ignore strings.)
Delete Files (Settings: Keep Thumbnails, Delete Empty Directories)
Upload the plugin files to the
/wp-content/plugins/upload-directory-cleaner directory, or install the plugin through the WordPress plugins screen directly.
Activate the plugin through the ‘Plugins’ screen in WordPress
Use the Tools->Upload Directory Cleaner screen to start the cleaning