Abstract: A self-contained illuminating device for mounting on or in a closed container for illuminating both the enclosed space of the container and an area of the device which has an insignia or graphic imposed thereon, e.g. for advertising purposes. The device has a shell made of a translucent material and a miniature light source. The shell is adapted to function as an optical waveguide for propagating light emitted by the light source down the shell while simultaneously illuminating surfaces of the shell bearing the advertisement. Additionally, the shell may include a light scattering element for distributing light at a periphery of the shell. The illuminating device comprises a circuitry, including a position-sensitive switch, e.g. a tilt switch, for activating the light source dependent on the position of the device.