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, spring onions must be washed before use. This is because you do not peel spring onions, you eat the parts of the onion that are exposed to soil, human handling and other contamination and spring onions tend to only be cooked lightly, not killing all the germs. Unwashed spring onions can cause food-borne illness, so it's important to wash them thoroughly before consumption.
Remove any visible dirt from the spring onions. Dirt commonly collects near the roots of the plants, but may appear on the leaves as well.
Peel off any discolouration on the leaves of the spring onions. If any leaves have become slimy, remove these as well. Spring onions should be firm if not crisp.
Place spring 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 spring onions, lay them gently on the paper towels to dry.
If spring onions are not thoroughly rinsed, contaminants on the onions could make you sick or cause food-borne illness.