Aslam, the freed slave of Sayyiduna Umar (may Allah be pleased with him), said that Sayyiduna Umar bin al-Khattab (may Allah be pleased with him) used to have water heated in a copper vessel and take his bath with it.
Abu al-Hasan said: This chain is sahih (authentic).
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 11