Cut a notch in a clean, empty plastic jar using a craft knife that runs from the lip of the jar to slightly past the threads that hold on the lid. A notch that is between 1/4-inch and 1/2-inch wide is suitable.
Put the string of lights inside the jar. Put the end of the string through the notch so that the plug is on the outside of the jar. Screw on the lid.
Measure the height and circumference of the jar. Cut the parchment paper so that the width is about a 1/2 inch longer than the circumference of the jar and the height is more than that of the jar. The exact height is up to you. Cut a small notch in the bottom of the paper that matches the notch on the jar.
Decorate the parchment paper. Use paints of any kind to paint on a design, inks for drawing or calligraphy, stamps, or glue on paper die cuts. Any object that is easily glued to paper is suitable for decoration.
Glue along one edge of the paper and glue the parchment into a cylinder. Let the glue dry. Slide the cylinder over the plastic jar with the notches matching so that the cord is easy to access.