To clean the baby artichokes, peel off the small leaves from the bottom and trim off the top inch. Use a vegetable peeler to peel the stem and taste it to see if it should be removed--if it's too fibrous, trim the whole stem off. Use a paring knife to trim the outside of the artichoke. Keep in water with lemon juice until ready to use to prevent oxidation. Before you begin, clean and wash the cockles or clams (or ask your fishmonger). Then, discard any cockles that have cracked. Rinse them with water, pour some salt over top and agitate with your hands to dislodge any additional sand. Drain and discard any cockles that are still open.