Sayyiduna Abu Tha'labah al-Khushani (may Allah be pleased with him) says: I asked the Messenger of Allah (peace and blessings be upon him): We go on military campaigns and travel through the land of the polytheists, and we need their vessels; may we cook in them? He (peace and blessings be upon him) said: "Wash them with water, then cook in them and make use of them."
Hadith Referenceالسنن الكبرى للبيهقي / كتاب الطهارة / 135