I saved my jam jar that I purchased from the Monks in Eagle Harbor Michigan with the Society of St. John. They run the Jampot from May til at least October, when I was there, selling jam and baked goods to help sustain the monastery besides any needed donations. I put a layer of glaze over the label to keep it as is because I liked the label. It is a 9 oz canning jar, but you can use a larger one. You would need to go to the hardware store for heavier hanging chain. I was able to hang this size with a heavy metal jewelry chain just fine. It is your option to decorate the jar anyway you wish. You could paint it. You could glaze it with half white glue and half liquidy acrylic paint that will become transparent as it dries. Test it on some glass before using it to see the desired effect.

Only needs a few tools: Canning jar of your choice with lid and screw on rim, small hammer, 2" common nail, wire cutters, round file, measuring tool, needle nose plyers to bend up the final piece of metal to cut off. You will also need appropriate chain, at least 36" long, and thin wire to mold chain to the jar later when hanging. You will also need appropriate hooks to hang the finished jar light as desired.

Step 1: CAREFULLY Prepare the Lid Opening

You may use the usual canning lid. As a mixed media artist I save everything and I used the end of a frozen orange juice container so I did not have to purchase the canning lids. It is the exact size to fit under the screw on rim for this size jar, of course you could never use something like this to can. I carefully hammered in a 2" common nail in a circular pattern after measuring the size of the Snap-in Socket Cord Set & Switch purchased at a local hardware store, approximately 1 1/4" diameter. You then carefully snip in between the holes with wire cutters, carefully using a round file to push down and file the ragged edges each time. I lifted the metal up for the last few holes, clipped off and finished filing.
Warning to be careful when filing that you do not push the file to the bottom and crack the glass, which is very easy to do without a light hand when using this kind of file. The burrs on the file catch the metal and snag, so you push harder and it gives quickly which can cause you to crack the glass if you are not very careful. Also be very careful of any of the metal edges, filed or not they are very sharp and dangerous!

Step 2: Inserting the Socket Cord Set

You would never want to hang the light from the cord set alone because it would put too much weight on the electric cord even if the jar is light. Be sure that the fixture is a good snap in fit by bending and filing the edge if a bit too small or using some type of trim tape or caulking you can fill in around the inside edge of the hole if you somehow cut it too large. The thin stuff by Scotch they sell in the insulation area of your hardware store. Measure twice, cut once!

I used 36" heavy charm chain to wrap around the lip of the jar, just under the rim of the cap, crossed the chain and brought both pieces to the sides, securing with thin jewelry wire. Please see the photos of the jar light as well as the schematic I wrote up to help, but it does look a little confusing as I read it. (1-2) The initial chain wrap is done after you have woven it with the jewelry wire. (3) You will also be weaving the jewelry wire in with the chain you are bringing back again to meet at each side of the jar, weaving the chain directly to the initial chain wrapped under the lip. (4) Secure and clip the wire at both sides and secure the ends of the chain, crossing a few links, again securing well with wire to hang. (5) You will end up with approximately 12" on either side in which to overlap.
You will need a heavy hook to hang in the ceiling or out from the wall as a sconce as desired. I am just using a large cup hook for this light, but would suggest a plant or light hook if using a larger jar.
I am only using a 7 watt night light in this, but according to the Socket Cord Set, it can take up to a 75 watt max. Be sure to keep the wattage in accordance to the surrounding material of your light fixture to avoid overheating or a fire.