I have allergies, but I still run outdoors, and sometimes I just gotta spit the phlegm out, butttttt, I spit it in the grass away from the track even though I hate to actually stop running and do that. Fortunately, I run in the mornings, and the track is pretty empty. The grossest thing I've seen is very large piles of dog crap in the middle of the track, and the other day there was a dead frog. I almost squished it, but seen it just in time, so I moved the poor thing with a stick into the grass. I've never had anything thrown at me, but I have had nasty comments hollered at me.