They Never Mention That Part

Who cleans the toilets on the Starship Enterprise?

There are a bunch of officers. And there are lots of juniors too, to get squashed by random alien life forms. They trot about looking important, and presumably they do button-stabbing ship-running-type things. And they have yeomen, whose primary function appears to be Captain's Toy.

But I've never seen any of them with a bog-brush in hand.