The Messenger of Allah ﷺ said: When any of you performs ablution, he should snuff up water in his nose and eject mucus. (Using translation from Abū Dāʾūd 140)  

أَنَّ رَسُولَ اللهِ ﷺ قَالَ «إِذَا تَوَضَّأَ أَحَدُكُمْ فَلْيَجْعَلْ فِي أَنْفِهِ مَاءً ثُمَّ لِيَسْتَنْثِرْ»