Getting Ready to Cut
Remove the bulbs from the fixture and stuff a rag inside the side marker side. This will minimize the amount of dust and debris that gets inside of the fixture. There will still be some that gets inside, however. Also, stuff a rag in the bulb holes for added protection.

Next, ready your dremel tool by putting on a good cutting blade. I used a "saw-tooth" type blade (about $10 at OSH) because it seemed to cut better than the disc, and made the hole a bit thinner. Although it seems geeky, I must encourage safety glasses. There is stuff flying all over, and the likelyhood of the blade breaking is good. Do yourself a favor - you might need that eye later :-)

Making the Cut
Now it is time to cut. First, cut the top of the light (top if it was still in your car). Follow the rubber strip as closely as possible. Click on the pic to see the line to follow. The depth of the cut is about 3/4 of the 1 1/4" blade I used. Cut slowly and check your progress often. You will be cutting through the grey plastic outside, then the clear plastic. If you see sparks when you are cutting, you have gone far enough. The sparks are from the metallic reflector in the back of the light.

Next, cut the side of the fixture. Use the brass torx head screw as your guide. Make the cut just inside of that screw. Do not go as deep as the top cut - there is less material here.

Finally, make the cut on the bottom of the fixture. There is a little valley between the clear part and the grey plastic portion. Make your cut as close to the clear plastic as possible. You will loose a bit of the grey plastic, but you will be able to fill it in with JB Weld. Go as deep as on the top side of the fixture.

Removing the reflector
Now that the cut is made, you can pry open the lens. If it does not open easily, there is probably some of the grey plastic that is holding it. Another hold-up may be the metallic reflector catching the end of the grey plastic. If that is the case, just bend gently until it comes out. Be careful if you insert a screwdriver or blade - it scratches easily.

Next, reach in with the needle nose pliers and liberate the orange reflector. It may put up a bit of a fight, as it is lightly bonded to the clear lens. Wiggle it around a bit and it will slide out. Pull it out gently so that you don't scratch the lens or metallic reflector

Cleaning up the mess
This step probably was the most time consuming - next to waiting for the JB Weld to cure. Lots of junk gets into the fixture during the cutting process. I experimented with a vacuum with a straw taped to the end. Worked, was painfully slow. Settled on compressed air.

First, use a small blade or the Dremel with a grinder to remove any annoying plastic shards around your cuts. Next, remove the rags that were put into the openings, and the one inside the fixture. With the compressed air, blow through the bulb openings while prying out on the lens opening. Repeat. Again. And again. You get the picture. Be careful in the headlight opening - there is a little "hood" that is pretty flimsy. Blow again.

Putting it back together
Once the fixture is as clean as possible, use some clamps and pieces of a rag for protection to pinch the fixture together. Focus on the top and bottom first and make sure you have sufficiently closed it up.

Next, mix up the JB Weld. I first tried with two-part epoxy, but found that to be way too runny. The JB Weld was a good consistency and did not leak into the fixture. Remember, only mix up a little at a time. The JB Weld sets up in about 4 minutes.

Spread the mixture on the top part of the fixture. Smooth it out with your spreading tool. You can also wipe off any extra with a rag if you are quick.

Repeat on the bottom of the fixture. Once the top and bottom is done, give it a bit to set up - I took a beer break at this point.

Once your beer is finished, you can move the clamps to do the end piece. I found it easy to move the clamps to the side, apply the JB Weld, then move the clamps as shown in the lower pic for the best pressure. The end piece wants to flex outwards.

Final thought on sealing - do a good job. I am sure it is impossible to seal it as well as the factory did, but you want to aim for that. Washing and rain will be the enemy here. Take your time and be thorough.

Spreading on the JB Weld

Finishing up
Once the JB Weld has hardened, you can use the Dremel again to grind down any rough spots(be sure to stuff your rags back in the bulb openings!). If you don't wait for the JB to harden, you will make a mess. Be patient.

Once you are happy with the finish, replace the bulbs and re-install into your Stang.

A note on the side-marker bulb - it is amber. It is supposed to be amber. If you put something other than that in there, you will probably be ticket bait. I read that Phillips is coming out with a bulb this fall that has a mirror finish when off, but glows amber when lit. That would be a nice addition. I will update when I find out some information.