@pled What are you doing for lung clearance?

Basic fundamentals of airway clearance include: hydration with mucinex and/or NAC tablet, inhalation of bronchial dilator, such as an albuterol inhaler (2 puffs), or levalbuterol through nebulizer, followed by 7% saline via nebulizer. Then use autogenic drainage and/or active cycle of breathing to clear your lungs. Check out the AD app if you have not already. This routine likely will set you up for a successful sputum sample along with a good clearance regimen for your lungs. It seems like a lot but it is manageable once a routine is developed.

Your most productive time ought to be first thing each morning because mucus pools in lungs over night.

Prior to the routine described above, my sputum samples were rejected time and time again. Frustrating. Anyway, give the routine a try and please report back!