Don’t know about the manatea, but the tea ball I leave some water in the pot to boil after I’m done, give the mesh a quick scrub with a toothbrush and pour the reboiled water over it. Gets most of the residual tea out, and every few months I give it a scrub with some soft dish soap. But yeah, a light patina will build up over time on stainless steel. Seasoning!
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