"Should I perform Wudu' after eating food that I see in the Book of Allah is permissible because fire has touched it?" Abu Hurairah gathered some pebbles and said: "I bear witness (as many times as) the number of these pebbles, that the Messenger of Allah ﷺ said: 'Perform Wudu' from that which has been touched by fire.'" (Using translation from Nasāʾī 174)
فَجَمَعَ أَبُو هُرَيْرَةَ حَصًى بَيْنَ يَدَيْهِ فَقَالَ أَشْهَدُ عَدَدَ هَذَا الْحَصَى لَقَالَ رَسُولُ اللهِ ﷺ تَوَضَّئُوا مِمَّا مَسَّتِ النَّارُ