The Pictures above show the eye balls I`ve been using in some of my skulls. The circuit is made up of
two red leds and a resistor (330 ohms). I made a round ball of clay layed it half way into a contain filled
with plaster. ( remember half way ) Once it dried I wet it with water to make it damp. Then I took my
Hot Glue Gun  and melted hot glue to fill the mold. when it cooled I drilled a hole in the center the size
of the led. (Maybe a little bigger than the led.  Remember leds come in different sizes and  briteness)  I
add power to the circuit to test the way the leds looked. Once I was happy with the way it looked I hot
glued the led into the eye. I cut away any extra glue that over flowed the mold  like in the center picture.
Here you see the eye all lit up. I may paint glow in the dark paint over the eyes so when the leds are
off they will glow a little. These eyes look great in a skull.