There are two sources of nasal snot: one is secreted by the mucous membrane glands of the nasal cavity; the other is tears. The mucous membrane of the nasal cavity contains many glands, which contain a kind of cup-shaped cells, and the cup-shaped cells secrete secretion every day, which is commonly known as nasal mucus, and the nasal mucus may also be mixed with dust or bacteria in the external environment. If tears cannot be discharged from the eyes in time, the tear glands can be connected to the nasal cavity through the tear ducts and nasolacrimal ducts, and some tears will enter the nasal cavity and participate in the formation of nasal mucus, some people will say a handful of tears and a handful of nasal mucus, that is the reason. If there is a lot of snot, it is recommended to clear it in time.