Every time i have a runny nose I'm comforting myself by thinking "It's ok, the body is getting rid of pathogens now"
But is that really the case ? does every 'drop' of nasal mucus contain pathogens ?
Nasal mucus is made out of " It is a viscous colloid containing inorganic salts, antimicrobial enzymes (such as lysozymes), immunoglobulins, and glycoproteins such as lactoferrin", writes the author of the wiki page of "mucus", citing https://www.ncbi.nlm.nih.gov/pubmed/12037568. Glycoproteins are proteins linked by polysaccharides (complex sugars)
https://journals.sagepub.com/doi/abs/10.1177/194589240501900203 nasal mucus often also contains the candida albicans fungus.
the prevailing belief is that snot is just a vessel to carry out pathogens, but as you see in the structural description there are immunoglobulins (antibodies), and antimicrobial enzymes, so the pathogens that get mixed up in it are also actively being destroyed.
I've been told all my life that, when one's sick, the change in color of the mucus is an indication of the levels of pathogens in the mucus. Regardless of whether or not that's actually what's going on (I've never blown my nose on a microscope slide), the mucus in one's body doesn't have pathogens as a fundamental component, but it is a vessel for immune cells that are specialized to act against pathogens, so it does seem to expect their presence. If your nose is running because your body is expelling pathogens there's a high chance that they're in the mucus coming out, otherwise it probably varies a lot, and might get to the zero point if your body (esp around your nose and throat) is totally pathogen free. Allergy runny noses might have more histamines, and runny noses on a cold day might be the most "blank", with nothing but inorganic salts, antimicrobial enzymes (such as lysozymes), immunoglobulins, glycoproteins, fungi, and whatever bacteria's in your nostrils.