Combining high and low probability densities in intensity hybrids, we study some of their properties in double-slit setups. In particular, we connect to earlier results on beam attenuation techniques in neutron interferometry and study the effects of very small transmission factors, or very low counting rates, respectively, at one of the two slits. We use a "superclassical" modeling procedure which we have previously shown to produce predictions identical with those of standard quantum theory.Although in accordance with the latter, we show that there are previously unexpected new effects in intensity hybrids for transmission factors below a 10 −4 , which can eventually be observed with the aid of weak measurement techniques. We denote these as quantum sweeper effects, which are characterized by the bunching together of low counting rate particles within very narrow spatial domains. We give an explanation of this phenomenology by the circumstance that in reaching down to ever weaker channel intensities, the nonlinear nature of the probability density currents becomes ever more important, a fact which is generally not considered -although implicitly present -in standard quantum mechanics.Deterministic and stochastic beam attenuation have been studied extensively in neutron interferometry, beginning with the work by Rauch and Summhammer in 1984 [1]. More recently, an interesting model of these results has been presented by De Raedt et al. [12] with the aid of event-by-event simulations, thus confirming the possibility to describe the known results even without the use of quantum mechanics. Our approach, in contrast,