Malik related to me from Nafi that Abdullah ibn Umar would spend the night between the two trails in the valley of Dhu Tuwa when he was approaching Makka. Then he would pray subh, and after that he would enter Makka by the trail which is at the highest part of Makka. He would never enter Makka, if he was coming for hajj or umra, without doing ghusl beforehand when he was near Makka at Dhu Tuwa, and he would tell whoever was with him to do likewise.
Muwatta Malik Book 20, Hadith 6
← Previous Hadith Malik related to me from Humayd ibn Qays from Ata ibn Abi Rabah that 'Umar ibn alKhattab once asked Yala ibn Munya, who was pouring out water for him while he was having a ghusl, to pour some on his head. Ya'la said, "Are you trying to make me responsible? I will only pour it out if you tell me to do so." Umar ibn al-Khattab said, "Pour. It will only make (my head) more unkempt."

Muwatta Malik Book 20, Hadith 5 Next Hadith → Yahya related to me from Malik from Nafi that Abdullah ibn Umar would never wash his head while he was in ihram except if he had to do ghusl because of a wet dream.

Malik said, "I have heard the people of knowledge say that there is no harm in someone who is in ihram rubbing his head with certain kinds of plants after he has stoned the Jamrat al-Aqaba but before he has shaved his head, because once he has finished stoning the Jamrat al-Aqaba it is halal for him to kill lice, to shave his head, to clean himself of body hair, and to wear normal clothes."

Muwatta Malik Book 20, Hadith 7