Lettuces have a hard, bitter core which is best removed. The leaves should also be washed to remove dirt and then thoroughly dried. Water left on the leaves will cause them to wilt and dilute arty dressing.
Discard any damaged outer leaves. Hold the head of the lettuce in one hand. Grasp the hard core in the other and twist it off.
Rinse the leaves well under cold running water, then submerge them briefly in a bowl of cold water.
Place leaves in a folded tea towel and pat dry (or use a salad spinner, see box). To crisp, refrigerate for at least 30 minutes.