Real Dictionary

clean up
phrasal verb: If the police or authorities clean up a place or area of activity, they make it free from crime, corruption, and other unacceptable forms of behaviour.
phrasal verb: If you clean up a mess or clean up a place where there is a mess, you make things tidy and free of dirt again.
phrasal verb: To clean up something such as the environment or an industrial process means to make it free from substances or processes that cause pollution.

clean up in American English
to make clean, neat, or orderly
to wash or tidy up

clean up in British English
to rid (something) of dirt, filth, or other impurities
noun: the process of cleaning up or eliminating something

clean-up
countable noun: A clean-up is the removing of dirt, pollution, crime, or corruption from somewhere.