Open the menu and choose to search for empty files and folders.
Certain system folders (such as the Trash, Temporary Items, etc.) are excluded from a scan for empty files and folders.
Expect to find some empty items in the Preferences, Extensions, and other system folders. If you still have the applications to which they belong, they can be ignored.
The items found during a scan for empty items are sent to a variation of a List window. The window is identical to a standard List window with the exception of a additional Ignore in Scans button next to the default button.