Cakradatta (Cikitsasangraha) 65.78

65.78

lohārakūṭatāmraja-
kaṭāhe dṛḍhamṛṇmaye praṇamya śivam .
tadayaḥ pacedacapalaḥ
kāṣṭhendhanena vahninā mṛdunā .. 78 ..

In a cauldron of iron, brass, copper, / or strong clay, having bowed to Śiva, / one should, remaining steady, cook that iron / with firewood over a gentle fire, (78)