Narrated 'Abdullah bin Hunain:

Abdullah bin Al-Abbas and Al-Miswar bin Makhrama differed at Al-Abwa';
Ibn 'Abbas said that a Muhrim could wash his head;
while Al-Miswar maintained that he should not do so. 'Abdullah bin 'Abbas sent me to Abu Aiyub Al-Ansari and I found him bathing between the two wooden posts (of the well) and was screened with a sheet of cloth. I greeted him and he asked who I was. I replied, "I am 'Abdullah bin Hunain and I have been sent to you by Ibn 'Abbas to ask you how Allah's Apostle used to wash his head while in the state of lhram." Abu Aiyub Al-Ansarl caught hold of the sheet of cloth and lowered it till his head appeared before me, and then told somebody to pour water on his head. He poured water on his head, and he (Abu Aiyub) rubbed his head with his hands by bringing them from back to front and from front to back and said, "I saw the Prophet doing like this."

حَدَّثَنَا عَبْدُ اللَّهِ بْنُ يُوسُفَ، أَخْبَرَنَا مَالِكٌ، عَنْ زَيْدِ بْنِ أَسْلَمَ، عَنْ إِبْرَاهِيمَ بْنِ عَبْدِ اللَّهِ بْنِ حُنَيْنٍ، عَنْ أَبِيهِ، أَنَّ عَبْدَ اللَّهِ بْنَ الْعَبَّاسِ، وَالْمِسْوَرَ بْنَ مَخْرَمَةَ، اخْتَلَفَا بِالأَبْوَاءِ، فَقَالَ عَبْدُ اللَّهِ بْنُ عَبَّاسٍ يَغْسِلُ الْمُحْرِمُ رَأْسَهُ. وَقَالَ الْمِسْوَرُ لاَ يَغْسِلُ الْمُحْرِمُ رَأْسَهُ. فَأَرْسَلَنِي عَبْدُ اللَّهِ بْنُ الْعَبَّاسِ إِلَى أَبِي أَيُّوبَ الأَنْصَارِيِّ، فَوَجَدْتُهُ يَغْتَسِلُ بَيْنَ الْقَرْنَيْنِ، وَهُوَ يُسْتَرُ بِثَوْبٍ، فَسَلَّمْتُ عَلَيْهِ فَقَالَ مَنْ هَذَا فَقُلْتُ أَنَا عَبْدُ اللَّهِ بْنُ حُنَيْنٍ، أَرْسَلَنِي إِلَيْكَ عَبْدُ اللَّهِ بْنُ الْعَبَّاسِ، أَسْأَلُكَ كَيْفَ كَانَ رَسُولُ اللَّهِ ﷺ يَغْسِلُ رَأْسَهُ، وَهُوَ مُحْرِمٌ، فَوَضَعَ أَبُو أَيُّوبَ يَدَهُ عَلَى الثَّوْبِ، فَطَأْطَأَهُ حَتَّى بَدَا لِي رَأْسُهُ ثُمَّ قَالَ لإِنْسَانٍ يَصُبُّ عَلَيْهِ اصْبُبْ. فَصَبَّ عَلَى رَأْسِهِ، ثُمَّ حَرَّكَ رَأْسَهُ بِيَدَيْهِ فَأَقْبَلَ بِهِمَا وَأَدْبَرَ وَقَالَ هَكَذَا رَأَيْتُهُ ﷺ يَفْعَلُ.