Apparatus and methods for maintaining flowability of solid-ink pellets when delivering solid-ink pellets from a container to an image-forming apparatus. The apparatus includes an extraction tube inserted into the container and connected to a vacuum source. Suction from the vacuum source impels pellets into the extraction tube through an extraction inlet, but pellet agglomerations may clog the system. Such a clog produces an immediate pressure spike within the extraction tube, an event detected by the clog detector. An actuator, responsive to the clog detector, drives an agitating structure that breaks up agglomerations and restores smooth pellet flow. Alternative embodiments can include devices having only the clog detector or the agitating structure. Alternative implementations of the agitating structure provide means for accomplishing pellet break up. The accompanying method detects the occurrence of a clog and responds by operating the agitating structure to break up agglomerations.