Sunan an-Nasa'i, Hadith 4260 ⓘ
It was narrated from Ibn' Abbas, from Maimunah, that: the Prophet was asked about a mouse that fell into the cooking fat. He said: "If it (the fat) is solid, then throw it away, and whatever is around it. If it is liquid then do not use it at all."(Daif)
أَخْبَرَنَا خُشَيْشُ بْنُ أَصْرَمَ، قَالَ حَدَّثَنَا عَبْدُ الرَّزَّاقِ، قَالَ أَخْبَرَنِي عَبْدُ الرَّحْمَنِ بْنُ بُؤْذُويَةَ، أَنَّ مَعْمَرًا، ذَكَرَهُ عَنِ الزُّهْرِيِّ، عَنْ عُبَيْدِ اللَّهِ بْنِ عَبْدِ اللَّهِ، عَنِ ابْنِ عَبَّاسٍ، عَنْ مَيْمُونَةَ، عَنِ النَّبِيِّ صلى الله عليه وسلم أَنَّهُ سُئِلَ عَنِ الْفَأْرَةِ تَقَعُ فِي السَّمْنِ فَقَالَ " إِنْ كَانَ جَامِدًا فَأَلْقُوهَا وَمَا حَوْلَهَا وَإِنْ كَانَ مَائِعًا فَلاَ تَقْرَبُوهُ " .
also referenced under: Book 41, Hadith 39 (In-Book) & Volume 5, Book 41, Hadith 4265 (DarusSalam)