'Clean Up Your Act' with These Phrases
If someone "cleans up their act", they have improved how they behave, or have started to follow the rules. This phrase is based on the idea that cleaning makes things the way they should be, while "your act" is how you behave in public. This comes from performers calling what they do on a stage their "act."
So if you had a roommate who never paid their rent on time, you might say to a friend, "If he can't clean up his act, we're going to have a big fight."
When cleaning, we sometimes "air something out" by putting it outside or opening a window. This lets fresh air move through it to make it smell better. But we can also "air a grievance." A grievance is something bad that has upset you or that feels unfair. So when we "air a grievance", we are talking about it and making it public.
So your friend might suggest that you discuss the problems with your roommate by saying, "You should talk to him and air your grievances."
In the past, people used pieces of slate, a kind of rock, to write on with chalk. If you clean the chalk off of the slate, you can start again and write something completely new. You can also call a new start "a clean slate".
So you might say to your friend, "No, I think I need a clean slate. I'm just going to find a new place to live."
