How to Clean the leeks. When you buy leeks buy the best quality fresh ones. Cut the leeks in to two. Divide stem and leeks from the middle. Cut the roots and throw it away. Peel off 1 0r 2 outer leaves. After cut the stem and top in middle to two. It will look like this and you can see the middle. Some times there is a harder flower stem in it. Remove that too . Look how it is. Dirty and muddy. Wash under running water until you remove the mud and the sand. After you can cut in to chunks for cooking.