I use Simple Green or vinegar with a scrub brush. Even if you completely sanitize the pot, there is probably more fungus on your bench, the ground under it, and spores everywhere in the air. Fungus is always among us. It is good to do a preventative spraying with a fungicide monthly in the summer. I lost two maples to fungus this season, and it looks like it may be three before it is over with. A Trident, a kyohime, and a ryusen.