Continuing the discussion from If dishwashers were Iphones:
It is. I actually tend towards the not full of shit end of the spectrum.
And this advice is good for cast iron or clay, as the link at the bottom indicates.
Caring for a cast iron teapot is very simple. Similar to the Yixing teapots, soap should not be used to clean an iron teapot. After rinsing the tetsubin cast iron teapot thoroughly with water, it should be wiped dry with a clean cloth. This cleaning method will allow the seasoned mineral coating to remain intact and protect the iron in the teapot walls from oxidizing.