The process of our lungs cleansing themselves after we quit smoking is quite amazing.
When we are horizontal (as in asleep), tiny hairlike organisms that line our airways "sweep".
"One of the respiratory system's defense mechanisms involves tiny, muscular, hair-like projections (cilia) on the cells that line the airways. The airways are covered by a liquid layer of mucus that is propelled by the cilia. These tiny muscles beat more than 1,000 times a minute, moving the mucus that lines the trachea upwards about 0.5 to 1 centimeter per minute (0.197 to 0.4 inch per minute). Particles and pathogens that are trapped on this mucus layer are coughed out or moved to the mouth and swallowed."
Sometimes the "crap" works it's way to our throat and just sits there making us feel like we can't clear our throats.
For me, this lasted well over a year.
http://www.merckmanuals.com/home/lung-and-airway-disorders/biology-of-the-lungs-and-airways/defense-...
