Work string-mounted cleaning tool and a method of assembling such tools using a quick release for the cleaning element. Oblong pad element has a curved upper surface with slots to receive work surface segments. Opposite edge has a part-circular recess with part-circular peripheral lip around an upper edge of the recess. A retainer fastening component in the recess has a core with socket adapted to receive a driving tool. The retainer is sized to permit it to rotate when mounted within the recess. Roll pins are provided for use in locating the fastener component in predetermined rotational configurations in relation to the recess. Shear pin is provided to inhibit unintended rotation of the fastener component, and to lock the retainer for normal use of the cleaning tool. Shearing of the shear pin permits disassembly of the tool.