A method and apparatus for deslagging a cyclone furnace in which a series of flexible hollow tubes are inserted into the combustion chamber and the explosive charges in each hollow tube are detonated sequentially. Each of the hollow tubes is biased outwardly against the accumulated slag and ash in the combustion chamber. The hollow tubes may be formed in arcs or rings in planes perpendicular to the longitudinal axis of the combustion chamber, and spacer rings may be positioned between each ring.