Trim the root ends off the leeks. Cut an X in the bottom of each leek. Remove any tough or discolored leaves, and trim the tops, leaving 2 inches of green. Cut an X, lengthwise, through the green part.
Place 10 cups (2½ quarts) of the water in a large bowl, and add the vinegar and leeks. Soak for 30 minutes to remove any remaining sand. Rinse the leeks thorough