Do you have midges?
Add one or two tablespoons of white vinegar to your washing water and the little insects will float like magic to the surface. Pour off the water and it's done!

Is your lettuce looking a bit downcast?
Immerse it into lukewarm water, then into ice water to produce a thermal shock; you'll restore all its vitality.

Last minute!
Always wash your lettuce just before coming to the table.

Always dress your salad greens at the last minute, otherwise the vinaigrette may cause them to wilt. The exception is fairly sturdy leaves (certain chicories, for example) that appreciate being tossed in advance so they can leisurely imbibe the tangy dressing.

Lettuce shuns cold
Lettuce is fragile and prefers the vegetable crisper of the refrigerator. It won't stand up to freezing. Do you have so much that you risk losing it? Then place it in bags and freeze it. You can use it like a green vegetable, or do as the Asians and chop it into soups.