Clean with warm soapy water followed by rinsing with clean water and drying with a soft cloth. All finishes are vulnerable to acid attack and some strong substances such as household cleaners or disinfectants can cause surfaces to go black or peel.
https://www.cphart.co.uk/dornbracht-xtool-concealed-thermostat-without-volume-control-12-inch-cdor0103650197900/cDOR0103650197900Dornbracht xTOOL Concealed Thermostat without Volume Control 1/2 Inch//www.cphart.co.uk//images/products/medium/cDOR0103650197900.jpg947.76947.76GBPInStock/shower-controls/cDOR0103650197900