[Machine] Al-Miswar ibn Makhrama and Ibn Abbas saw a person washing his head while being in the state of ihram (sacred pilgrimage clothes). They sent me to Abu Ayyub Al-Ansari and asked me, "How did you see the Messenger of Allah ﷺ washing his head while in the state of ihram?" So I came to Abu Ayyub and found him between the two corners of the well, with a cloth covering him. I greeted him and he pulled the cloth closer to him. I said, "My cousin Ibn Abbas sent me to you to ask how you saw the Messenger of Allah ﷺ washing his head." Abu Ayyub then motioned his hands over his head, moving them forwards and backwards.  

امْتَرَى الْمِسْوَرُ بْنُ مَخْرَمَةَ وَابْنُ عَبَّاسٍ فِي غَسْلِ الْمُحْرِمِ رَأْسَهُ فَأَرْسَلُونِي إِلَى أَبِي أَيُّوبَ الْأَنْصَارِيِّ كَيْفَ رَأَيْتَ رَسُولَ اللَّهِ ﷺ يَغْسِلُ رَأْسَهُ وَهُوَ مُحْرِمٌ؟ فَأَتَيْتُ أَبَا أَيُّوبَ وَهُوَ بَيْنَ قَرْنَيِ الْبِئْرِ وَقَدْ سُتِرَ عَلَيْهِ بِثَوْبٍ فَسَلَّمْتُ عَلَيْهِ فَضَمَّ الثَّوْبَ إِلَيْهِ فَقُلْتُ أَرْسَلَنِي إِلَيْكَ ابْنُ أَخِيكَ ابْنُ عَبَّاسٍ كَيْفَ رَأَيْتَ رَسُولَ اللَّهِ ﷺ يَغْسِلُ رَأْسَهُ؟ «فَأَمَرَّ يَدَيْهِ عَلَى رَأْسِهِ مُقْبِلًا وَمُدْبِرًا»  

who said that he saw the Prophet disrobing for his Ihlal and to perform Ghusl. (Using translation from Tirmidhī 830)   

«أَنَّ النَّبِيَّ ﷺ تَجَرَّدَ لِلْإِهْلَالِ وَاغْتَسَلَ»