Abstract: Smeltable dust and pieces of grate slag in the proportions in which they are produced by a garbage incinerator can be disposed of by simultaneously melting them in a low-shaft electric furnace having at least one electrode extending into a molten slag bath which is maintained in the furnace covered by a layer of coke. The dust is introduced below the coke layer by a lance or tubular electrode while the pieces of grate slag are introduced above the molten slag both. The proportions of the two are maintained so that the leachate from the solidified slag when deposited in a landfill, conforms to the statutory requirements of clean drinking water laws.