Visine has worked wonders for me. I smoke in a field down the road from my house, and when I feel like going back I just use a couple drops in both eyes and head back to take a shower. My eyes don't get extremely red, but if you really look it's noticable. I always carry around Visine, some kind of perfume or scented spray, and my NORML Freedom Card (http://norml.org/index.cfm?Group_ID=3407) just in case.