The Best Ways to Keep Your Eyes from Watering While Cutting Raw Onions
Slicing, dicing or chopping a raw onion can be hazardous, and not just because of the knife. The fumes they emit can cause the eyes to burn and water uncontrollably. Do not resort to buying the dehydrated variety. The problem can be prevented using a number of easy methods. Before getting started, use one of the very best ways to keep your eyes from watering while cutting onions, and slice, dice or chop them without crying.
Wear Swimming Goggles or Other Eye Protection
The best way to stop the burning and watering is not necessarily the most comfortable. If the eyes are protected, the gases cannot cause irritation. Glasses might help, but they will not stop the irritating fumes from coming in contact with the eyes. Put on a pair of swimming goggles or safety goggles. You might look a bit silly, but you will not have to deal with the pain and accompanying tears.
Turn on a Fan
The use of an ordinary fan is also one of the best ways to keep your eyes from watering while slicing, dicing or chopping particularly pungent raw onions. If the kitchen has a ceiling fan, turn it on at the highest setting. Otherwise, point a portable fan toward the cutting board. It will move the gases that cause burning and watering away from your face.
Cut Raw Onions under Running Water
Cutting raw onions under running water will also work when trying to prevent your eyes from watering. Place the cutting board in the sink, and turn on the cold water. It does not have to be on all of the way. Just a small stream of water will eliminate or at least reduce the gases that are released when the cells are opened.
Place it in the Freezer for Fifteen Minutes before Slicing
Another one of the best methods of prevention takes a little more time, but it really works to stop the eyes from watering. When planning to slice, dice or cut up raw onions, place them in the freezer for about 15 minutes before preparation. They will not be frozen solid in that short amount of time, but the cells that would usually emit irritating gases will be hindered by the extremely cool temperature.
Source: http://cooking.stackexchange.com