Sunan Abi Dawud Book 28, Hadith 108
The tradition mentioned above (No. 3833) has also been transmitted by Ibn Abbas from Maymunah, from the Prophet (ﷺ) like the tradition narrated by az-Zuhri, from Ibn al-Musayyab.
The Prophet (ﷺ) said: When a mouse falls into clarified butter, if it is sold, throw the mouse and what is around it away, but if it is in a liquid state, do not go near it.
Al-Hasan said: AbdurRazzaq said: This tradition has been transmitted by Ma'mar, from az-Zuhri, from Ubaydullah ibn Abdullah ibn Abbas, from Maymunah, from the Prophet (ﷺ).
when a fly alights in anyone’s vessel, he should plunge it all in, for in one of its wings there is a disease, and in the other is a cure. It prevents the wing of it is which there is a cure, so plunge it all in (the vessel).