We use cast ron almost exlusively here in the western U.S. One of our several Dutch Ovens is well over 100 years old and still going strong. You can wash the vessels in warm water and a light detergent, dry thoroughly and then, as has been suggested, wipe down the interior surfaces with a paper towel soaked in any good vegetable oil... we use olive oil. Be sure to do this after each use.
Since they haven't been used for a while, then clean, oil and place in an oven at about 300 degrees F for half an hour or so. Upon removing them, let them cool and then wipe them down again before storing...