And cleaning can wear away important features, so don't do it if you don't have to. You can measure the humidity with two thermometers, some cotton wool, two rubber bands and a small bowl of water. Brass will stay bright for a considerable time and only requires occasional cleaning but candle wax can corrode candle sticks and should be removed with hot water. Bronze can be cleaned occasionally with pure furniture wax and brushed up lightly with a bristle brush. Don't attempt to straighten bronze as it fractures very easily.
Bronze is brittle because it's an alloy.
Alloys are made up of two or more different metals which often don't mix well allowing fractures to occur between concentrated areas of each metal. Carpets and rugs need to be moth-proofed if you are storing them. Don't wash them unless it's essential. Use a solution of two tablespoons of white vinegar to a pint of water for bes results and dry with cloths and a hairdryer. Stains can be removed using two tablespoons of salt to a pint of water.