Mucus/Phlegm is classified a pathogen called “Dampness” in Traditional Chinese Medicine (TCM). It is shown in the pulse as what is called a “slippery” pulse, similar feeling to a rolling pearl. Mucus is a “normal, slippery and stringy fluid substance produced by many lining tissues in the body.” In is created as a response for instance to allergens, outside and inside pathogenic influences, the common cold. It is called phlegm when in the lungs. 
From a TCM perspective lungs are the receptacle of phlegm but not the root cause. We expel it from the body in various methods.
Symptoms of Dampness in TCM include masses, lethargy, indigestion, cough, dizziness, headache, as well as other health issues.
What helps: From a TCM perspective, you can drain, sweat, and excrete Dampness in many ways. Typically it is recommended to avoid dairy, sugar and sweets, greasy foods, or extremely cold foods. Weather can affect Dampness in the body such as Winter or during the hot muggy late summer.
Foods such as warm soups can help to eliminate “Dampness” and herbs such as ginger.
Walking and sweating can help with the “dampness”.
So next time you your acupuncturist may mention “Damnpness ” pertaining to mucus and phlegm you’ll have at least some background knowledge to help you learn more.
This article is not intended to diagnose. Please consult a Licensed healthcare provider for any medical related conditions.