The Prophet ﷺ said, "Whoever performs ablution should clean his nose with water by putting the water in it and then blowing it out, and whoever cleans his private parts with stones should do it with odd number of stones."  

عَنِ النَّبِيِّ ﷺ أَنَّهُ قَالَ مَنْ تَوَضَّأَ فَلْيَسْتَنْثِرْ وَمَنِ اسْتَجْمَرَ فَلْيُوتِرْ