One of the tetsubins I have came with its original box, and inside the box are two inserts. One is a list of the artist’s achievements — awards, shows, etc that he has been in (among which was apparently a purchase by the emperor!). The other, though, is rather interesting and which I neglected to read when I got it — it’s about caring for the tetsubin.
The first part of it is rather simple and not worth mentioning, but the last part has four points, which are rather interesting
1) Use pure water, rather than tap water. If you have to use tap water, then you should let it sit for a night before using it — and only skim off the top, not the whole container. The bad stuff, such as whatever chlorine or anything else they use, will sink to the bottom, so they say
2) Use a mild heat to dry the thing out thoroughly after use, and let it sit uncovered for the night so that it doesn’t trap moisture inside. That’s sensible.
3) Use a cotton cloth that’s slightly damp to wipe the outside of the kettle after use, while it’s still warm. That I didn’t think about at all
4) Never use it on a gas stove, it’ll crack the damn thing.
I wonder what the damp cloth will do. Maybe I should try doing that from now on.