He used to narrate from the Messenger of Allah ﷺ that he said, "Perform ablution after eating anything that fire has cooked."
حدثنا محمد بن جعفر قال حدثنا شعبة عن أبي بكر بن حفص قال سمعت الأغر قال سمعت
يحدث عن رسول الله ﷺ أنه قال توضئوا مما أنضجت النار
Its isnad is sahih. Abu Bakr bin Hafs is Abdullah, and the hadith has come up many times before, see 9487. Many jurists did not act upon it, because it was abrogated, as mentioned before and as will come in the hadith that the last practice of the Messenger of Allah ﷺ was to abandon wudu for what fire had touched.