I started vaping 2 months ago, never smoked cigarettes...i got into nicotine through hookah and some vaporizers, and i just recently started to notice that i start coughing/spitting brown stuff. Sometimes it has a brown chunk in it. I've read alot of posts and most have this problem but they quited smoking. I really dont knoe what is this brown stuff and im starting to think its vaping what causes it. I also want to mention that i have a family member in my house which is a heavy smoker. So i dont know if he/she causes me any health problems. I also want to mention that im using a 50%(VG)/50%(PG), with 11mg nicotine.