A scheme for removing foreign material from the surface of a substrate by directing a high velocity aerosol of at least partially frozen particles against the foreign material to be removed. Different schemes are described for accelerating the frozen particles to very high velocities sufficient for particle removal, removal of organic layers (e.g., hard baked photoresist or ion implanted photoresist) and removal of metallic layers. In one embodiment, liquid droplets are entrained in a high velocity gas flow and the resulting gas/liquid mixture is passed through an expansion nozzle to produce a high velocity aerosol of frozen particles. In another embodiment, frozen aerosol particles are entrained in, e.g., a sonic or supersonic gas jet before impacting a surface to be cleaned. The cleaning aerosols may be applied to substrates inside a vacuum chamber or directly from a hand-held device. Also, various scanning systems are described for achieving substantially uniform exposure of the substrate to the cleaning aerosol.