Antonyms for the term "cleaned it up" could be "made it messy", "sullied it", "contaminated it", "dirtied it", "polluted it". These words showcase the opposite action of making something clean and tidy. Instead of tidying up something, the opposite would be to mess it up or dirty it. These antonyms can be used in various contexts such as cleaning up a room, cleaning up after cooking or preparing something, cleaning up a spill, and so on. Using antonyms enhances our understanding of various terms and also helps us to broaden our vocabulary.