I wish I could do snot rockets...but my snot just flows and flows. I run with a hanky in my hand year-round. During the warm months I use it to wipe sweat, in the cold it gets half soaked with snot during an hour run and on a 2 hour run it is fully soaked. Gross. But better on the hanky that goes in the wash with my sweaty workout clothes than ON my clothes, heh. I have pretty overactive sinuses (thank god for my neti pot).

Haven't biked in really cold weather, yet. Cold = lots of snow. On a bike I have a feeling the snot issues would really be a pain.