40 Treatment of common metals; treatment of precious metals; development of photographic and cinematographic films; photocomposing, photographic printing, photogravure; drying, canning, freezing, smoking and preserving of foodstuffs; providing information in the field of food manufacturing; slaughtering of animals; leather working and fur conditioning; saddlery working; textile treating, wool treating; tailoring, embroidery; framing of works of art; treatment of liquids, chemicals, gas and air for industrial use; grinding of glass and optical glass; custom assembling of materials for others; services of a dental technician; pottery firing; production of energy; rental of generators; paper treating; printing, bookbinding; treatment of plastics.