Hi doctor. i used to smoke weed but left smoking 32 days before. now my sputum comes black and brown but mostly black. so i should be worried..!

No, lung cleaning: Smoking paralizes the "mucocilliary elevator, " a slow upward flow of mucus from the lungs to help remove particles too big for white blood cells to "eat" and dispose of. Can take a week to a month per year of regular smoking to "clean house." you have to do the rough math, since tobacco usually heavier use than mj. Lungs will work better when process is done!