  We analyze the flow and clogging of circular grains passing through a small
aperture under vibration in two dimensions. Via Discrete Element Method
simulations, we show that when grains smaller than the original ones are
introduced in the system as an additive, the net flow of the original species
can be significantly increased. Moreover, there is an optimal radius of the
additive particles that maximizes the effect. This finding may constitute the
basis for technological applications not only concerning the flow of granular
materials but also regarding active matter, including pedestrian evacuation.
