Citronella candles or torches filled with citronella oil are often used in outdoor settings to deter flying insects like mosquitoes. In addition, the light from these can add a festive touch to an outdoor gathering. This variation on that theme employs empty wine or beer bottles to make tiki torches. Construction is simple, and you can easily find the supplies you need.
Wrap nylon plumbing thread tape around the narrow end of the copper pipe fitting until it fits snugly into the mouth of the wine bottle. The fit should be solid enough that it doesn't fall out easily, but loose enough that you can remove it easily for refilling the oil.