I have read three methods: A. Bake the kettle for 15 min @ 350F in an oven. B. Boil 3 to 4 inches of water until it all evaporates. C. Boil 5 gallons of water for 15 min. Has anyone preformed any of the methods above with successful results? Or better yet, does anyone have any other way to passivate a new aluminum kettle? Thank you for your time, cheers!