Mishkat al-Masabih 411
‘Abd Khair said:
We were sitting looking at ‘Ali when he performed ablution. He inserted his right hand, filled his mouth, rinsed it, snuffed up water and ejected the mucus with the left hand, doing this three times, then said, "If anyone is pleased to look at God's messenger’s method of performing ablution, this is how he did it.” 

Darimi transmitted it.
وَعَنْ عَبْدِ خَيْرٍ قَالَ: نَحْنُ جُلُوسٌ نَنْظُرُ إِلَى عَلِيٍّ حِينَ تَوَضَّأَ فَأَدْخَلَ يَدَهُ الْيُمْنَى فَمَلَأَ فَمَهُ فَمَضْمَضَ وَاسْتَنْشَقَ وَنَثَرَ بِيَدِهِ الْيُسْرَى فَعَلَ هَذَا ثَلَاثَ مَرَّاتٍ ثُمَّ قَالَ مَنْ سَرَّهُ أَنْ يَنْظُرَ إِلَى طَهُورِ رَسُولِ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ فَهَذَا طَهُورُهُ. رَوَاهُ الدَّارمِيّ