Okay to answer part of my own question, I found nutritional benefits but no internal cleansing uses:

Lemon, Orange, and Grapefruit peel are loaded with d-limonene, which studies show has cancer-protecting activity against a variety of cancers^5-10. A recent study from University of Arizona concluded that consuming citrus peel can reduce the risk of skin cancer by 30%¹. When citrus peel is consumed together with hot black tea, the risk of skin cancer is reduced by more than 70%¹. Additional laboratory tests conclude that d-limonene, which comprises more than 90% of the oil found in citrus peel, reduces not only the incidence and size of tumors at several sites, but also the growth of various tumor cells^2-8.

"You don't have to consume much citrus peel to help protect yourself against skin cancer," said Iman A. Hakim, M.D., Ph.D., University of Arizona College of Public Health and Arizona Cancer Center. "As little as one tablespoon of zest per week is enough to make a significant difference." One tablespoon of zest is equivalent to the peel of approximately one orange or lemon, depending on the size of the fruit and how finely or coarsely the zest is grated.

Research on the Mediterranean diet, a diet that often includes parts of the whole lemon and citrus oils, also concludes that citrus peel is beneficial to health. Persons such as those living in the Mediterranean area that consume large amounts of citrus fruit, have the lowest incidence rates for cardiovascular diseases and most tumors associated with diet¹¹. A common beverage of the region is Mediterranean-style lemonade, which is prepared from the whole fruit, including the peel, which adds d-limonene to the diet.

Gourmet chefs have been using lemon and orange zest for years to add intense, delicious flavor to recipes. The discovery of new health benefits may encourage consumers to add citrus zest to everyday meals such as soups, salads, salsa, or sprinkled on top of chicken or fish.

Portions of a lemon or orange differ in their content of health boosting substances. According to studies, the two main differences between citrus peel and juice are that the peel contains a higher concentration of ascorbic acid. In addition, citrus peel contains higher concentrations of d-limonene as well as other active components known to fight cancer (such as hesperidin, naringin, and auraptene) than do the juice and pulp¹.

http://www.sunkist.com/snb/press/06_03_skin_cancer.asp

Happy Cleansing,
Peanut

Master Cleanse for Mind & Body
http://curezone.com/blogs/f.asp?f=811