In this paper, we report on the observation of dusts measured by InfraRed (IR) and visible (VIS) cameras in Tore Supra and in JET. The formation and transport of dusts in both Tokamaks during normal operation and disruptions are discussed. Dense hydrocarbon clouds, which might be a possible pathway to the formation of spherical nanoparticles, are always observed by the IR cameras inside the MARFE region in the JET divertor during the deuterium puffing phase before the density limit disruption. We suggest utilizing this phenomenon for a density limit disruption warning and safety feedback signal.