How to keep salad makings from wilting?

We often buy a bag of lettuce with shredded cabbage, onion, carrot, etc., as a base for salad. It’s hard to keep it for more than one day, however, because the lettuce tends to wilt, even if the bag is properly reclosed. What should we do to keep perfectly good salad makings from wilting?

Lettuce wilts because the moisture has escaped, but all the good stuff is still there in the leaves. Take the wilted lettuce, and give it a soak for 15 minutes or so in a bowl of water with a splash of vinegar added. It should freshen up nicely. A trip through the salad spinner, and you’re good to go.
You can slow down the wilting process by putting a damp, but not dripping wet, paper towel in the bag with the lettuce.