system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do lungs manage to heal themselves when someone has quit smoking after being a smoker and inhaling tar for multiple years?

Can the lungs ever remove all the tar that was inhaled?
gpt
The tar is constantly being cleaned by cilia and mucous, so the cleaning part isn't really a major surprise.  The body finally wins when the crap is no longer constantly added.  The "healing" part though is not quite true.  Lots of damage cannot be repaired.  You won't regain elasticity to lungs that lost it, and the scar tissue won't ever get returned to normal.  Sometimes it is too late when the smoker quits.