The upper sash of our double hung windows has no control to keep it from sliding down. Many of them are resting on giant nails that were hammered in *cringe* before we bought the house. I am about to begin a full restoration of each window including putting back the sash stays on the lower sashes where they were removed. I want to know what to use for the upper sashes. A sash stay on the face of the frame would interfere with the movement of the lower sash. I know there has to be something out there but I can't seem to figure it out. BTW these are not weighted.