Musnad Ahmad 1163:52

'Abd al-Rahman narrated to us, from Malik, from al-Zuhri, from 'Ubayd Allah ibn 'Abd 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. He said: "Take it and what is around it, and throw it away."