Musnad Abu Ya'la al-Mawsili 216:1

Abu Khaythama narrated to us, Sufyan ibn 'Uyaynah narrated to us, from al-Zuhri, from 'Ubayd Allah, from Ibn 'Abbas, from Maymunah, that the Prophet (peace and blessings of Allah be upon him) was asked about a mouse that fell into ghee and died. He said: "Discard it and what is around it, and eat it."