I too never was quite able to produce anything but never asked why that might be so. However, I learned, thanks to needing to buy a new compressor and special Pari nebulizer cup for the Tobramycin i was prescribed earlier this year for 28 days, that apparently — my guess anyway given the info leaflet describing what needed to be happening that arrived with the Tobramycin —, the previous compressor and cup were for me anyway, was not providing small enough particles and enough pressure out of the cup of the 7% saline during the session to work. Once I continued using the PARI ProNeb Max and the PARI cup just for the 7% saline, I began to produce lots of mucous using the breathing technique followed by the huffing and coughing. When I have completed the session I feel better too and sleep well.