This paper outlines the history of the installation of the dehumidified showcases for the display of corroded copper alloy objects in the Department of Western Asiatic Antiquities in the British Museum. It discusses in detail two showcases from different exhibition galleries, describing the method of construction, and the equipment used to maintain a steady relative humidity value of 40% or less. The associated problems of monitoring the environment, and obtaining accurate readings of relative humidity and temperature are also considered in an attempt to assess the success of a system which has been in operation for longer than fifteen years. -- AATA