Very simple, Empty Folder Cleaner.
Annoying with many empty folders in file manager app? Then, this is for you.
* On Android 4.4 Kitkat, This app CANNOT clean external SD cards. It’s because of Google’s policy: ANY 3rd-party apps can’t access to external storages. (except some custom firmware users)
Screenshots
[appbox googleplay pe.kmh.EmptyFolderCleaner]