(1) باب الْفِطْرَةِ
Al-Mu'tamir narrated that his father said:
"I heard Talq mentioning ten things that have to do with the Fitrah: Using the Siwak, trimming the mustache, clipping the nails, washing the joints, shaving the pubes, rinsing the nose, and I am not sure about rinsing the mouth."
Reference: Sunan an-Nasa'i 5041
In-book reference: Book 48, Hadith 2
English translation: Vol. 6, Book 48, Hadith 5044