If the cookware is metal you can use electrolysis. Car battery charger clamped with an electrode to sacrificial metal plate and an electrode to cookware; both

If the cookware is metal you can use electrolysis. Car battery charger clamped with an electrode to sacrificial metal plate and an electrode to cookware; both hanging apart from each other in a bath of electrolyte made of water + sodium carbonate. Let it work for a day or so in a well ventilated area (it will create hydrogen gas).