Sahih Muslim Book 2, Hadith Number 502.

Chapter : Characteristics of Fitra.

‘Aisha reported: The Messenger of Allah (may peace be upon him) said: Ten are the acts according to Fitra: clipping the moustache, letting the beard grow, using the tooth-stick, snuffing water in the nose, cutting the nails, washing the finger joints, plucking the hair under the armpits, shaving the pubes and cleaning one’s private parts with water. The narrator said: I have forgotten the tenth, but it may have been rinsing the mouth.