We've all heard the old adage about an apple a day. But to get the most out of that apple, here's a tip: Don't peel it.

Apple peels contain natural chemicals that can help lower cholesterol, control blood sugar and perhaps even protect against cancer.

Potato skins have nutritional appeal as well. They're a good source of fiber, iron, potassium and b vitamins.

Before you enjoy these or other skins and peels, be sure to wash them off. Don't use soap or detergent, though. Cold water—and a little elbow grease—are all you need.