While you needn't be too concerned with washing white, red or sweet onions because you peel off the outer layers that were exposed to soil, outdoor elements and germs, green onions must be washed before use. This is because you do not peel green onions, you eat the parts of the onion that are exposed to soil, human handling and other contamination and green onions tend to only be cooked lightly, not killing all the germs. Unwashed green onions can cause food-borne illness, so it's important to wash them thoroughly before consumption.
Things You'll Need
Remove any visible dirt from the green onions. Dirt commonly collects near the roots of the plants, but may appear on the leaves as well.
Peel off any discoloration on the leaves of the green onions. If any leaves have become slimy, remove these as well. Green onions should be firm if not crisp.
Place green onions in a strainer and rinse them with cool water. Turn onions to make sure all sides are thoroughly rinsed.
Lay out a layer of paper towels on a counter or table surface. When you are done rinsing green onions, lay them gently on the paper towels to dry.
If green onions are not thoroughly rinsed, contaminants on the onions could make you sick or cause food-borne illness.