Fruits and vegetables with a peel
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Fruits and vegetables with a peel

Produce with a peel retains the least amount of pesticide. The "Clean 15," according to the Environmental Working Group, are onions, corn, pineapples, avocados, asparagus, peas, mangoes, eggplant, cantaloupe, kiwi, cabbage, watermelon, sweet potatoes, grapefruit, and mushrooms.