regarding an animal, e.g., a mouse or some other animal that had fallen into solid or liquid oil or butter-fat: I had been informed that a mouse had died in butter-fat whereupon Allah's Messenger (ﷺ) ordered that the butter-fat near it be thrown away and the rest of the butter-fat can be eaten.
Reference: Sahih al-Bukhari 5539 In-book : Book 72, Hadith 65 USC-MSA web (English) : Vol. 7, Book 67, Hadith 447 (deprecated)
Help us gift a modern, ad-free Islamic application for the Muslim Ummah. Your donation will be recorded as Sadaqah Jariyah in your book of deeds, In Sha Allah.