Dismantling a Gas Furnace

I have a gas furnace in the house i just bought. I converted everything to electric. The gas company came over and dug up my yard to cut off the gas since i only use electric. I want to tear down the gas furnace to get some money out of it.. I simply do not have the tools to do so.. I tried unscrewing the screws but they are almost impossible. does anyone know how I can break it down and separate the metals? I brought all the ducts to the scrap yard today and i actually got made fun of because of the kind of metal i had and the amount