Replacing house window screening and spline Demonstrated by Frank, of Gilberts Hardware: Screens for house windows are easily replaced with new screening and spline. The spline jams the screen material into the frame. The screening material is aluminum or fiberglass. Colors for metal screening are silver, black or bronze, and fiberglass is black. The spline material is rubber or plastic in grey or white. Aluminum screen is stronger, but harsh winters will leech oxidized aluminum onto the window glass leaving spots. Remove the screens every fall when you wash the windows. The spots come off with Easy-Off oven spray. Fiberglass screens have a shorter life than metal, but do not spot and are lighter. Screening may be patched rather than replaced. Homeowners can use a piece of old screen or sew thread over the hole. It works fine, but can be a tedious job. Some plug holes with small doodads glued on either side of the screen, like a plastic dragonfly and colored glass.