The lemon tree is very pretty, and the lemon flower is sweet. But the fruit of the poor lemon -- well, you know the rest of the lyrics. But lemon juice, like other citrus juices, also contains alpha hydroxy acid, which penetrates and removes the protein glue that causes dead skin cells to stick to your epidermis [sources: Baran, Berthold-Bond]. Manufactured exfoliants often contain big doses of AHA -- so much, warns Sophie Uliano, a skincare advisor to actress Julia Roberts, that they can cause your skin to become more sun-sensitive. In 2008 Good Housekeeping magazine interview, Uliano recommended making your own citrus exfoliating mask. Mix one-quarter-cup each of lemon juice, apple juice, grape juice and cane sugar in a glass jar, making sure the sugar completely dissolves. Then apply the mixture to your face with a cotton ball, and leave it on for 10 minutes before rinsing it off.