Al-Qasim bin Muhammad said that a man came to Abdullah bin Abbas (may Allah be pleased with him) and said: O Ibn Abbas! I have camels; I lend them out for their milk and for riding, and there is an orphan in my care who also has camels. What is lawful for me from my orphan's camels? Abdullah bin Abbas (may Allah be pleased with him) said: If you search for his stray camels, apply tar to the mangy ones, repair their drinking troughs, and water them on their turn, then drink without harming their offspring and without draining all the milk.
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الوصايا / 12670