Just thought I'd post a video of a method of physio that I do. This can be done on my own or with percussion from someone at the same time.
It's a BiPaP machine and compressor linked up together. I take 8 breaths at a time holding each for 2 seconds. While I breathe in, the BiPaP machine pushes extra air into my lungs to shift the mucus. I then do a 'huff' where I take a big breath in and force it out again causing me to cough up the mucus. In the chamber I have hypertonic sodium chloride which the compressor activates to stop the breath in being so dry making it easier to cough up the mucus.
I usually do 5 cycles on each side or until I've stopped coughing up the mucus.