Rubber/plastic waste need gasification process in order to achieve a complete combustion. Rubber waste will be placed on the water cooled grate and strong induced draft will sack the flue gas downward and lead the gas to the high temperature second combustion chamber where wood and/or coal will be used to maintain the furnace temperature. When gasified gas from the 1st chamber will pass through the 2nd chamber, carbon will have enough distance and time to finish its combustion. However, we need to maintain the temperature even after the 2nd combustion chamber by installing an additional oil burner to produce turbulance and maintain the temperature for unburnt gas to completely finish burning before entering to the boiler convection tube area where the gas temperature will be instantly drop below its igniting point. Size of the said oil burner must be decided in accordance with the condition of the waste by experiment.