If there are clumps of dirt or a layer of grime that you do not want to contact your cutting board or knife, give the onion a rinse under the tap. This step is optional since you will be peeling away all outer layers of the onions anyway, but if you are particularly nervous about bacteria or contaminants, peel away the flaky layers of onion, then rinse and dry it very well before proceeding with the steps outlined in the article.