Nebulizer tubing should not need to be cleaned. It is only the conduit for air from the compressor to the mouthpiece, and should never get any mucus or saliva in it. If you see moisture in the tubing at the end of a session, it is condensation. Disconnect the mouthpiece and let the compressor run for 5-10. The dry air from the compressor will dry the tubing.

Tubing should be replaced as often as you replace your nebulizer assembly - docs varyingly recommend 3-6 months. With my Pari, if using daily, I replace it at 3 months. When I order the nebulizer (cup and mouthpiece) it is a kit, which includes new tubing, so it is replaced at the same time. This has been the practice in our house for over 30 years.

Sue