Abstract: A hand tool is insertable between a flexible window-retaining gasket and the frame of the vehicle to separate the gasket from the frame so that a flexible deformable strip material may be fed through the tool and inserted between the gasket and the vehicle. The tool includes a support portion and an end operative portion, offset from the support portion and having included passageway therethrough for the insertion of the deformable strip material. A tool guide portion is provided at the extremity of the tool adjacent the exit point of the passageway.