Musnad Abu Ya'la al-Mawsili 155:1

Abu Ya'la Ahmad ibn Ali ibn al-Muthanna informed us, Muhammad ibn al-Minhal, the brother of Hajjaj al-Anmati, narrated to us, Abd al-Wahid narrated to us, from Ma'mar, from al-Zuhri, from Sa'id ibn al-Musayyib, from Abu Hurayrah: The Messenger of Allah (may Allah bless him and grant him peace) was asked about a mouse that fell into ghee. He said: "If it is solid, remove it and what is around it. And if it is melted or liquid, do not eat it."