It is narrated from Sayyiduna Abu Tha'labah al-Khushani (may Allah be pleased with him); he said: I said: "O Messenger of Allah, we go to the land of the People of the Book." Then I asked him (peace and blessings be upon him) about their vessels, and he (peace and blessings be upon him) said: "Wash them, then cook in them."
Hadith Referenceالمعجم الكبير للطبراني / باب اللام ألف / 18823