Some people have all the luck. First, my friend Missy and her family found themselves moving to Naples when her husband was reassigned by the Air Force. Then, soon after she arrived, Missy was introduced to the fine art of trash-picking by a group of friends addicted to finding and reusing the demijohn bottles that literally litter the area. All that litters my corner of the world is those ubiquitous plastic grocery bags, but Missy and her friends are fortunate enough to find collectible bottles in trash heaps by the side of the road!

Demijohns are short-necked vessels used to transport liquid or hold it during fermentation. Missy has seen several ways they've been repurposed: Some folks paint the bottles. Others build small scenes inside (like a ship in a bottle but on a grand scale). Missy took advantage of the metal working skills of a local family to turn her bottles into the large scale candle holders seen above.
Missy does report a degree of amusement from her Italian friends who are puzzled by her use of what they see as trash to decorate her home, but I for one am in love. Apparently the new mayor of Naples is working to clean up the piles of trash by the side of the road which is good for the city but not so good for Missy and her friends who nevertheless continue their quest to save these wonderful demijohns.
(Images: Melissa Ledesma-Leese)

Shaw's Original Fir...
Love them! Wish I could get a candle holder for mine. My Norwegian mother in law had a couple long forgotten and half buried by the side of her summer house, we dug the biggest out and it is proudly in my living room. She used to use them to make cider when my husband was little.
It seems you could start a pretty decent little Etsy shop selling these "trash to treasure" bottles for a decent profit to other parts of the world that don't have them!
The candles are cute, but why waste them when they could be used to ferment "liquid"?
fabulous! How do you clean them out? I have several gallon-size glass jugs I'd like to use (for actual fermenting, though).
Quick! Hand me a lamp kit!
@suzeh: I have several old and large demijohns and this is how I cleaned them.
First of all, and especially if your bottles are very big, I would be sure to do this outside, on a soft surface -- either on a lawn or ideally in a sandbox. The bottles are heavy enough on their own, and of course when they have water, etc. inside they become more unwieldy and also slippery. You don't want to break one!
Start by putting some sand in the bottle -- maybe a cup or so, depending upon the size of the bottle. Then add a bit of water. Then, carefully swish the sand/water around in the bottle to touch all the inside surfaces.
The sand acts as an abrasive to help scour the glass.
When the bottle looks clean, empty out the water and sand, rinsing well. Since you're planning to use them for fermenting, I would then add a water/bleach solution to the clean bottles, filling them to the top, to make sure any contaminants are taken care of. I'd let the bottles sit for a while and then carefully empty and rinse them.
Rereading your post, I see that your bottles are one-gallon size, so perhaps doing them inside would be OK. Mine are mega-sized -- bigger than the largest ones pictured on this post -- and I was so afraid of breaking one, hence the extra precautions.
Good luck!