I never really liked this string of bats. Just too commercialized for my haunting taste,  so I hacked them into my no "vacancy" tombstone.

Here's what they look like lit. Should be pretty neat color for the tombstone. Here's a video of them fading in and out.

These were easy to de-light. Just pull them out of the holographic cardboard.

Here are the lights "un-batted". There are 108 lights total, so that should be plenty, as they all fade in and out together on this strand...

Here is just the paper after cutting straight down at the edges of the letters, remembering to do the inside of the A's and the O first.

Here I used the regular dremel bit to clean out most of the letters. If you move too quickly through the foam you will burn it and get hard melted pieces...

Here is a letter close up with the foam burned in it. Next I took my carpenter's knife and separated the thin edges that didn't get cleaned out by the round dremel bit.

After cleaning out the excess with my knife, I took the regular "router" bit for the dremel and cleaned up the bottom of the letters.

Here is a close-up of it cleaned up. 

I tried to drill the holes for the lights, but it just ripped up the foam so I simply took my bit (7/32) and pushed it through to the other side. It worked pretty well.

Here's what the back looks like after making the holes. Not perfect, but that's okay...

Here is where I pushed the lights in (same photo as above) and I had major problems with some of the lights going out, so I pulled them out and will fix them tonight. But, when I did try them, they looked really good. The purple light fills the whole letter but you can still see the separate lights so it looks like a theater marquee. Really cool effect. Also, the foam glows around the letters a little too which adds a neat mysterious look. I'm hoping it will still do that once its painted...

I got frustrated with the lights, so I painted the letters for a break. I still have to add a shape to the vacancy stone and some cracks and aging effects before I finish painting. I'm going to try one of those expensive faux granite ones from the Depot. Fingers crossed...

Please remember to saturate the letters with the latex paint as it looks more professional, and will protect the foam totally from the finishing spray paint.

I just used wood putty to cover some of the lines in the foam from the manufacturer. The stuff works great. It sanded and painted beautifully.

Here it is pained. We used a black textured paint on it but it wasn't enough texture to really notice. Regular black paint would have been the same as far as looks. It does feel textured, but that won't matter during a haunt, obviously...

Here is the foam backing we're going to use to hide the extra lights and cords...we're going to carve out four holes at the corners, put in some Elmer's wood putty, and then screw on the back piece.

Note: DO NOT HAVE YOUR LIGHTS ON WHEN INSERTING THEM INTO THE FOAM. Ours started to smoke badly as it was burning the foam and paint as we were pushing them in. As a result, the inside of the letters are now a royal mess. We lost a lot of foam during the process. Make sure your bulbs are clear of the foam before turning them on.

Other "vacancy" tombstone websites for reference: