I would like to share a technique that I discovered by accident and that is pretty helpful to clean your lungs when you have abused of cigarettes or any drug that you have smoked. I started practicing meditation, and because of that, I started taking big and deep breaths by my nose, and exhaling through mouth, I have realized that since I started doing this, my respiratory system has been recovering, I used to suffer of rhinitis, and used to be unable of smelling food or anything because I smoked a lot of cigarettes a couple of years ago. Since I started taking this deep breathings I started to eventually (2 or 3 times a day) sneeze and when I get this soft sneezes I take out a little amount of smoke out of my mouth, and eventually with days that amount of smoke that goes out of my lungs has been day by day reducing, ultimately I recovered my smelling capacities, and when I sneeze a little amount of smoke come out of my mouth compared to when I started sneezing, so i think that is a natural way of cleaning out your lungs and has been pretty helpful for me. I expect this could help people out there, is just as easy as a deep breath by your nose, retain air a couple of seconds, and then exhale by your mouth, any question, feel free to ask. Regards and best wishes with your recovery.