2Remove any bruised outer layers from the leeks. Trim off to the roots, leaving the root end intact. Trim the tops of the leeks on the diagonal, leaving 2 inches of the green part attached. Cut the leeks in half lengthwise, and submerge in a large bowl of cold water to clean them. Shake the leeks well to dislodge the dirt stuck inside. Let them sit a few minutes, to allow any grit inside the layers to fall to the bottom of the bowl. Repeat the process until the water is clean. Place the leeks, cut side down, on a towel and pat dry completely.