Musannaf Ibn Abi Shayba 35:170

Hushaym narrated to us, from Abd al-Aziz ibn Suhayb, from Anas ibn Malik, who said: Some people from Uraynah came to Medina and found its climate unsuitable. The Prophet, may Allah bless him and grant him peace, said to them: "If you wish to go out to the camels of the charity and drink from their urine and their milk, then do so."