Janitor is a small addon that removes all 120 buttons from your action bars. This is useful, especially when installing a new UI with custom action bars; oftentimes these don't match up with your previous bars. Instead of opening configs, digging around for bars that may or may not even be defined, Janitor simply lets you start fresh, with your new UI!
Janitor is also useful when setting up your own custom UI, when a fresh install leaves you with a bunch of 'blank' buttons (old macros, as yet undefined), or any other circumstance that requires fast, automated removal of all buttons.
Removal of all action buttons is permanent. To prevent accidental removal, a popup box will ask for confirmation before removing any button.