Shoko rokuti kununisa (smelt) rinoreva kunyngudutsa matombo ane simbi kuti simbi ikwanise kupatsanurwa kubva kumatombo acho. Nokuti simbi inorema kudarika matombo, inodzika pasi pebhaera, tsvitsvo (slag) ichisimuka yoyangarara pamusoro pesimbi. Tsvitsvo zvinoreva murara asina simbi anoyangarara kana matombo ose achinge anyauka. Chivanda zvinoreva utare hwakanuniswa asi usina kucheneswa kuti tsvitsvo ibve. Bisiro - (pottery kiln, altar censer). Nyawutsiro (smelting furnace) Saghala neTaita vanoti kuteleka (Smelt). Baila vanoti ku tenta butale (to smelt iron) vachireva kunyautsa utare.