Sahih Muslim 1382
Sahih Muslim · Book 15: The Book of Pilgrimage · Al-Madinah eliminates its Dross and it is also called Tabah, and Taibah
This hadith has been narrated by Yabya b. Sa'id with the same chain of transmitters (and the words are):
وَحَدَّثَنَا عَمْرٌو النَّاقِدُ ، وَابْنُ أَبِي عُمَرَ ، قَالاَ حَدَّثَنَا سُفْيَانُ ، ح وَحَدَّثَنَا ابْنُ الْمُثَنَّى ، حَدَّثَنَا عَبْدُ الْوَهَّابِ ، جَمِيعًا عَنْ يَحْيَى بْنِ سَعِيدٍ ، بِهَذَا الإِسْنَادِ وَقَالاَ " كَمَا يَنْفِي الْكِيرُ الْخَبَثَ " . لَمْ يَذْكُرَا الْحَدِيدَ .
" Just as a furance removes impurity," but no mention is made of iron.