37 maintenance, cleaning and disinfecting of buildings, rooms, washrooms, refuse apparatus, sanitary apparatus, kitchen equipment, air conditioning apparatus, ventilating apparatus, humidifiers, water storage apparatus and water supply apparatus; installation and replacement of receptacles for waste materials and articles; installation, replacement, replenishing, cleaning, maintenance and repair of vending machines, drying apparatus, air filtering apparatus, air freshening apparatus, air treating apparatus and of apparatus and materials for office, toilet, washroom, cleaning, sanitary and hygienic purposes; advisory and consultancy services relating to the cleaning and maintenance of washrooms; clearing of blockages in pipes, drains, and sewers