My friends are smokers and so am I. Every morning they ll wake up and spit black/brown tar like mucous. I smoke just as much if not more than them but I ve never had the problems they have. I ve looked it up and some say it s just the lungs getting rid of tar build up and I ve seen people saying that if this happens people should see a doctor. Is it really that concerning or is it just a build up of tar exiting your system?