I had an old leftover store bought prop from last Halloween.   It is a plastic plaque that has a skull on it with RIP written above the head.  The one with a glow in the dark sticky rubber tongue. (similar to the sticky hands or sticky spiders you get in gumball machines)  I wasn't going to put it out this year, but some neighborhood kids were asking about it.  The g.i.t.d. eyes had fallen off and I figured the thing was shot.  I thought, "maybe I could add some light up LED eyes to spark up this old thing.

I had a bunch of Blue Bucky Eyes From Anatomical Chart Company http://www.anatomical.com.  These things are about $2 a pair or less.  They are soft and clear.  Perfect for lighting up. (Don't get the brown ones, they are not clear or soft)

Here, one has the LED installed.

Radio Shack has 10mm red LED's that looked to be the perfect size for this project. Catalog #: 276-086.  I calculated the resistor to be 330ohms, for use with a 9 volt battery.  I only had 1k resistors on hand so I put 2 in parallel resulting in a 500 ohms load.  This resulted in a pretty good brightness.  The size of the LED is about 3/8 inch, so I used a 3/8 wood bore bit to cut a hole in the eye.

Here I show the wood bore bit I used to cut into the Buck Eye

Bucky Eyes are made from soft rubber and they are hollow.  You could really cut into them with a Xacto knife.  I used a wood bore and held the eye in a vise.  After this, I just slid the LED into the hole in the eye

Buck Eye after the hole was cut.

I wired 2 LED's in parallel to a switch and a 9 volt battery holder.  Here is the back of the prop.  You can see the circuit here.  There are plenty of sites which will explain how to wire up LED's so I wont detail that here.  If you have any questions, email me.  I soldered everything, but you could twist it together and cover with electrical tape as well.

I glued the eye to the prop with crazy glue. (not shown here)

Here are the eyes lit up.

The final product in the dungeon.  Yea, the prop is cheesy, but now I like it because of the eyes, and the kids love the gooey tongue.