Wear goggles. You might look silly, but wearing airtight eyewear is 100 percent effective in preventing tears. The gas that irritates your eyes is released by a chemical reaction that occurs when the cells of the onion are broken. Several companies make special “onion goggles,” but any eyepieces that keep air out will work. “For some steampunk flair, try antique motorcycle goggles.”
Chop near an open flame. “If you’ve got a gas stove, fire up one of the burners.” When you do your chopping nearby, the flame will suck in the troublesome gas. A high flame works “shockingly well”; using a low flame “left us misty-eyed.”
Use cold water. You can also try slicing an onion while it’s immersed in cold water or chopping it while cold water runs over your hands. Either technique “will send all those tear-jerking chemicals down the drain.”
Source: Mental Floss
