Protestors have thrown them back, but typically the police don protective goggles & masks before they deploy the gas so it may not be the most effective thing.

Protestors have thrown them back, but typically the police don protective goggles & masks before they deploy the gas so it may not be the most effective thing. There was also a video going around of a protestor in HK placing a traffic cone over the canister and dousing it with water to defuse. It looked to do the trick. Lots of protestors have the belief that a handkerchief soaked in vinegar will have some type of "neutralization action" against the gas when worn tightly around the face - watch protest videos and you'll see this in action. I have no idea if the vinegar has any actual effect on the chemical or if a wet barrier just keeps it from being easily inhaled.