Sue (volunteer mentor) posted an excellent video of Dr Pamela McShane discussing airway clearances. Her recommendation is 7% saline followed by breathing exercises. This information should be in every Pulmonary Clinic. I have had such a hard time producing sputum and following Dr. McShane's recommended procedures has been life changing. I am coughing less, my airways feel clear, etc. She also referenced a UK study with 100 participants, 55 tested positive for MAC or someother bacterium and at the end of the 1 year study, nebulizing 6% saline, only 15 tested positive for MAC.