system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do the lungs get cleaned from dust that managed to get there?

So assuming I'm in an environment with a lot of dust (or any other particles) in the air and breathing it all the time.  
I guess that most of it are being filtered by my nose and breathing tunnels but small fraction will eventually make it all the way to the lungs.

I'm curious how the body gets rid of that "grabage" in the lungs? Does is it stay there forever?
gpt
your lungs have little hairs inside called cilia, they brush all the crap up.

They basically get rid of all the dirt. 

Funny fact, smoking kills them, so you get even more crap in your lungs and when you stop smoking for a week or so and they regrow, they start removing crap from your lungs, so then you start seriously coughing.