1. A window-cleaning tool for facilitating cleaning of windows, the window-cleaning tool comprising: an interior window-cleaning utensil configured to be held by a human hand while gliding the utensil across an interior surface of a window; an exterior window-cleaning utensil configured to magnetically couple with the interior utensil through the window while in contact with the exterior surface of the window, the exterior utensil being further configured to move along the exterior surface of the window in a manner that mirrors the movements of the interior utensil as it moves across the interior surface of the window; and a fluid-delivery system including a fluid pump, a fluid-conductive tube, and a fluid-delivery mechanism, the fluid-conductive tube being operatively connected to the exterior utensil, the tube being configured to tether the exterior utensil to keep the exterior utensil in reach in case the utensils decouple; the fluid pump being operatively connected to the exterior utensil via the tube, the fluid pump being configured to pump fluid through the tube to the exterior utensil; and the fluid-delivery mechanism being operatively connected to the exterior utensil and to the tube, the fluid-delivery mechanism being configured to deliver fluid pumped through the tube to the exterior surface of the window.