@picartist The NJH, National Jewish Hospital/Clinic, doctor indicated to me that one may not bring up much mucus during the routine session but will often later in the day, after having done the morning nebulizing, with being active etc.
Movement of the body during the day especially if one bends and raises while doing things helps, if one doesn't have a problem with the lungs when one bends over. Not everyone can bend over due to certain conditions with the lungs or acid reflux.
The important thing is that you feel you are bringing up the mucus. It could eventually work more for you in the nebulizing session also.
What do you mean by "damage" in the lower lung?
Barbara