Intuit wrote:CZ, tight-fitting top, thoroughly drain first. I wouldn't leave any vessel with wet tea sitting overnight with the lid off, especially if you live in a wetter area of the country or live in a dwelling with known mold problems.
It might be a useful datapoint that all my experiments were done in Los Angeles - a very dry place. I've had mold grow several times in drained, tight-fitting, closed yi xing, but never in an opened yi xing. YMMV.