Most bottle cutting projects are easy to dry out after cutting, because you’ve opened it up into a wide, accessible container. For projects that leave the bottle intact, such as lamps and filled bottle ideas, a good clean and smear free drying is essential. The cleaning part is very easy, using a soak in very hot water with a little washing up liquid, giving good results even on really dirty street salvaged bottles with everything from mud, slugs and decaying flora inside shifting in the end. A thorough rinse is essential to remove all the detergent traces before drying begins.
At first, I was inserting paper/cloth towels with along thin pointer, and rotating them to dry them, which was ok, but far from satisfactory. Even days of leaving them to dry out naturally wasn’t always successful, leaving the odd drip and streak. Heating the bottle with the gas torch was a bit too severe in terms of heat when holding, and tended to transfer condensation from one side of the bottle to the other, without clearing it out rapidly. I did toy with the idea of adding desiccant inside, but that would cause as much if not mess as you try to remove when saturated.
This left two options I could think of, the first being the gas oven. Placing them in the pre-heated oven on a low gas mark for a few minutes worked well, but it meant a very hot bottle hads to be picked up, and stored somewhere, though you could just turn the oven off and leave it to cool if it’s not in the way. This worked fine, but is not recommended for bottles you intend retaining the label on. One of mine turned into a bit of a disaster on that front – scorched and glue everywhere.
The second option was just standing them on the hearth, in front of the gas fire for a few hours, which is usually on anyway at this time of year. Though slower, the end results are perfect, and leave a sparkling clean bottle ready to use. This is now my preferred cleaning and drying method of getting a really clean full bottle to use.