Gather your skeleton keys.
Cut some decorative ribbon to match the color of the window shades that you have in your house. For example, cut yellow ribbon for a bedroom you've decorated in yellow, blue for your blue kitchen and white for your screened-in porch. Make the ribbons long enough that you can loop them through the ends of the keys and make at least a medium-sized bow.
Make a knot at the end of the rope pull on your window shades.
Tie the skeleton keys onto the knotted window shade ropes using the matching pieces of ribbon that you cut.
Remove the protective glass from the shadow box. Set it aside.
Choose a decorative liner for each shadow box; this will make the keys stand out. Extra pieces of wallpaper, old newspapers, some brown butcher paper and calico fabric offer some examples of materials that would be appropriate for this project.
Glue the decorative liner to the inside of the shadow box. If the shadow box is compartmentalized, glue a different type of backing in each compartment. For example, in the box's large compartment square, add a piece of wallpaper. Paste an illustration from a 1940's catalog in another.
Place the skeleton keys in the compartments. Add them to the wall of the shadow box with glue, hook-and-loop tape -- such as Velcro brand -- or tacks.
Add other decorative elements to the shadow box, such as antique buttons, old medicine vials or old coins.
Cover the front of the shadow box with the protective glass that came with it.
Position a tall candle in an antique jar. You'll have to hold the candle in place until you can fill the jar with the other materials.
Fill the jar with clear glass marbles and at least one skeleton key each; do this gently to avoid breaking the glass. However, the more skeleton keys you can put into the jars, the more interesting this arrangement will look.
Repeat this process until you have enough jars to create a centerpiece on your table.
Arrange the jars so that the tallest jars stand in the middle and the shorter ones off to the sides. Make sure that you have a good view of the keys inside the jars.