Appendage for a robot

The present invention relates to a horizontally movable and downwardly biased appendage that extends laterally from a surface treating apparatus, such as a robotic floor cleaner. The robotic floor cleaner and/or appendage may use disposable cleaning sheets, such as dust clothes, wipes, sheet-brushes, and the like, to clean under objects or into corners but does not substantially interfere with the rotation of the surface treating apparatus about its axis when it is adjacent to encountered obstacles. The appendage can extend under low hanging obstructions to remove dirt, and reach into comers innavigable or unreachable by the robotic floor cleaner.