The invention relates to a method for operating a furnace, wherein a starting material comprising at least one metal element is molten, wherein the starting material is heated by at least one burner that is operated with a fuel volume flow of a fuel and an oxidant volume flow of an oxidant. An exhaust gas temperature of the furnace is monitored in an exhaust gas line at least at one measuring point downstream of a post combustion zone, wherein in a standard operational state a target fuel volume stream and a target oxidant volume stream is fed to the burner, wherein a change of the exhaust gas temperature is recorded at predetermined time frequencies and is compared to a predetermined threshold value. The invention is characterized in that when the change of the exhaust gas temperature per time unit is greater than the threshold value, the burner is put into a reduced operational state for a predetermined time, wherein the quotient of fuel volume stream to oxidant volume stream is lowered by at least one of the following actions: A) a predetermined sudden reduction of the fuel volume stream to a reduced volume stream and B) a predetermined sudden increase of the oxidant volume stream to an increased volume stream, said quotient being reset to the standard operating state after the reduction period.