1. Mfe nnukwu bọtịnụ.Nnukwu bọtịnụ agaghị arapara n'etiti mkpịsị aka gị, ụda ahụ na-adịkwa nro mgbe ịpịrị ya obere.
2. Manganese ígwè stamping.A na-etolite ahụ mgbịrịgba site na stamping nke efere ígwè manganese, nke dị oke ma na-adịgide adịgide, adịghị mfe nchara, ma nwee ezigbo mmebi siri ike.3Efere elu.A na-eji varnish na-eme achịcha na-ebipụta ụkpụrụ n'elu, nke na-adịghị mfe ịla nchara na nchara, ma nwee nnukwu gloss.