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)
عَنِ النَّبِيِّ ﷺ أَنَّهُ سُئِلَ عَنِ الْفَأْرَةِ تَقَعُ فِي السَّمْنِ فَقَالَ إِنْ كَانَ جَامِدًا فَأَلْقُوهَا وَمَا حَوْلَهَا وَإِنْ كَانَ مَائِعًا فَلاَ تَقْرَبُوهُ