Remove the solar, bulb and battery pieces from the garden light; with most lights, this is a simple process in which the solar panel on the top simply pops or pries off. Use a small flathead screwdriver if necessary. Snip off extra casing; all you want to remain attached to the solar panel is the wiring to the battery housing, the battery housing and the light.
Remove the jar's lid and set it aside. Spray the exterior of the jar with frosting spray and allow it to dry completely before proceeding. Spray a second coat if necessary.
Heat up your hot glue gun. Dot glue around the underside of the jar's lid, close to the edges. Attach the solar panel to the underside of the clear lid, solar panel side facing down and touching the glue. Allow the glue to completely dry before proceeding.
Glue the battery and light component to the underside of the solar panel so they won't hang down freely, if they are only connected by wires. Allow the glue to dry.
Screw on the jar's lid and place it somewhere sunny.