This work aimed to characterize the deportment/concentration and liberation/association of the metals and light elements within mechanically processed waste printed circuit boards (PCBs) that hold the complex and heterogeneous structure and distribution of different material components. Waste PCBs passed through a series of mechanical processing (i.e., comminution and sieving) for metal recovery and were then characterized without further destroying the particles in order to capture their heterogeneity. The characterizations were performed in a laboratory and large-scale neutron facility. The results obtained with a portable X-ray fluorescence spectroscopy and prompt gamma activation analysis were compared and confirmed the good agreement and complementarities in general. The advantages and disadvantages of the two different methods were identified and discussed in this paper, in relation to their application to the analysis of mechanically processed PCB particles.