Ah, colds!! We have 4 children who had allergies, plus the usual mucous, sometimes running into pneumonia, diarrhea. By finding the cause of their allergies, food related--milk, fats etc. they gradually outgrew the worst part, but still have to be careful of acidic foods, etc. and they are all now in their 40's and 50's!
By addressing the basic culprit, you can avoid using so much medication, which usually just offers a temporary relief, if that. I also have trouble and when I used the cool, moist air vaporizer, it would send me into bronchitis----the same as being outside on a cold, damp day, but now I take Claritin or an equivalant, every day, an asthma inhaler, Dr.,ordered, and have not had a cold for several years. Our kids still have to be careful of cold drafts etc. Good Luck!! It seems that there are more allergies out there, these days, and your body naturally builds up phlegm to dispell the excess mucous---
Also, I worked at a hospital for 30 years and found that the moist vaporizer was moldy inside, and was putting out germs, and most of us at the nurses station, kept getting strep!! Which stopped, after they removed the offending vaporizer@!