As a moslem, everybody know about 'wudlu'. 'Wudlu' is something must do before go to pray. Purposes of 'wudlu' activities is purification, by using water. Wudlu has six 'rukun'. 'Rukun' mean minimum requirement to make that activity approved. Approved by who ? Of course conform and accordance to ritual guidances, Al - Qur'an and Hadits.
What are the contents of 'Rukun Wudlu' ? First is intention for God. Second is washing your face. Third and further is washing the hands until your elbow, washing your head including some hair, and washing your feet from toe until your ankles. Last is all of that must be carried out in an orderly manner.
Often we see somebody doing wudlu with additional activities like washing the hands and nose in first, and then gargling. While washing their head, someone also washing their ears. Washing your hand, nose, ears, and gargling is additional activities of wudlu.
I have a funny story about that when my ustadz ask to me about 'rukun wudlu'. To answers that, i speak that washing the hand is 'rukun', but actually not. I'm wrong. Those just some recommended activities. But, though only as additional activities, all of that is reasonable and recommended activities because some reason.
About washing your hand, the reason is when you do the activities of wudlu, you use your hand -as a tools- to clean up your body. You must think, " when you clean up your body with your hand, how your body become clean, if your hand is dirty ?".
Rasulullah doesn't like the smell of the mouth and somebody sniffed their snot, especially when praying. To avoid this condition, you must gargling and washing your nose. ... Or you have another reasonable activity as alternative ?
How about washing the ears ? Dirty ears make tickling. Itch ear make your pray not good. And because of that, you better wash your ear before praying.  haris fauzi, 31 dec 2013