The Prophet ﷺ was asked about a mouse that had fallen into butter-fat (and died). He said, "Throw away the mouse and the portion of butter-fat around it, and eat the rest."
سُئِلَ النَّبِيُّ ﷺ عَنْ فَأْرَةٍ سَقَطَتْ فِي سَمْنٍ فَقَالَ أَلْقُوهَا وَمَا حَوْلَهَا وَكُلُوهُ