Tracking Down Dirty Windows - Window washers' elevator is demonstrated on rood of new Lever House, 24-story window wall and stainless steel building under construction at Park Avenue and 53rd Street. Car runs on roof tracks and supports a push-button scaffold which runs on vertical tracks down the sides of the building. Device is needed because windows of completely air-conditioned building do not open. There is no place on sheer glass walls where a washer can climb put or fasten a safety belt.