Reply:  You can clean the glass using Morsø Glass Cleanser. This must be done when the stove is cold. If heavy soot built-ups appear, use treble ammonia water to clean the glass. Soot may appear on the glass if the combustion temperature is too low or if the air controls are used incorrectly. The secondary air controls must be open and the primary air controls closed. The primary air either from the riddling grate or air control are only to be used during the lighting period or when dry wood is put into the stove. Morsø recommends a moisture content in the wood of 16-20%