Abstract: A sonic cleaning device and method for removing accumulated fine particles from surfaces such as in heat exchangers using sonic energy vibrations. In the invention, a gas is passed through a tube having internally corrugated walls and having the tube outlet end attached to the inlet end of an expanding horn. The gas flows past the corrugations at high velocity and produces high intensity sonic vibrations within the tube, and the vibrations are amplified by passage through the horn. The horn outlet is directed at a surface to be cleaned and the accumulated particles are fluidized by the sonic energy and removed from the surface by the flowing gas and/or by gravity.