"It reached 'Umar that Samurah had sold some wine, and he said: 'May Allah ruin Samurah! Does he not know that the Messenger of Allah said: May Allah curse the Jews, for animal fat was forbidden to them, but they rendered it.' Sufyan (one of the narrators) said: "Meaning: They melted it down."
Sunan an-Nasa'i Book 41, Hadith 36
← Previous Hadith "Allah, the Mighty and Sublime, and His Messenger have forbidden the sale of alcohol, dead meat, pigs and idols." It was said to him: "O Messenger of Allah, what do you think of their fat of dead animals, for it is used to caulk ships, it is daubed on animal skins, and people use it to light their lamps?" He said: "No, it is unlawful." Then the Messenger of Allah said: "May Allah, the Mighty and Sublime, curse the Jews, for Allah forbade them the fat (of dead animals) but they rendered it, sold it, and consumed its price."

Sunan an-Nasa'i Book 41, Hadith 35 Next Hadith → a mouse fell into some cooking fat and died. The Prophet was asked (about that) and he said: "Throw it away, and whatever is around it, and eat (the rest)."

Sunan an-Nasa'i Book 41, Hadith 37