Trays were already in use in upper-class households back in the 17th-18th century and to this day it’s impossible to imagine a home without one. Tromsoe is made of a combination of glass and metal. The rim is finished with pressed, powder-coated metal sheeting and the inside is lined with a silver mirror. A characteristic of genuine silver is that some dark spots may develop over time. The Tromsoe tray should be cleaned only with a slightly damp cloth. Do not use any harsh cleaning products. The tray should not be immersed completely in water.