The sputtering yield of Mo honeycomb walls was compared with the yield of fiat walls in a d.c. Ar glow discharge. Under the experimental condition where the mean energy is approximately 1 keV and the angle of incidence of primary ions strongly distributed around normal, the yield is reduced by a factor of 20 to 30. Before and after the bombardment, the surface topography of the honeycomb targets was observed by a scanning electron microscope.