or discharge end as can be seen from fig1 the upper part of the conduit 18 is tapered inwardly to discharge opening 32 and oriented such that abrasive which impacts against the walls tends to ricochet toward opening 32 the debris and abrasive are directed toward the cleaning apparatus primarily if not solely through the action of the kinetic energy remaining in these materials after they have been popelled against the surface to be cleaned however rotating broom 33 is located within chamber 14 to sweep material which does not have sufficient kinetic energy to find its way to discharge opening 32 broom 33 can capture the stray abrasive and debris and sweep them into the propelled abrasive stream to give it sufficient kinetic energy for collection purposes within the conduit 18 in the alternative the broom can generate energy or be located such that the material captured by the broom is directed with sufficient energy into conduit 18 so that the material swept by the broom will be propelled along in the main rebounding particle stream and be collected at the discharge opening 32 from the conduit 18 the collected abrasive and debris are directed through the discharge opening 32.