You've probably heard of many methods for cutting glass. Some of them involve wrapping string soaked in alcohol around a bottle, setting it on fire and the glass cracks. Another is cutting a score mark then using a blowtorch to pop apart the pieces at the scores line. All of them have a downside; about half will be left with stress cracks or crooked edges and you either ditch the bottle or grind or sand down the edges until they're perfect.
There is a simple way that involves a regular glass cutter and water. Either use the DIY method - which is more difficult since you have to hold the bottle perfectly aligned to create a single score line - or buy a device you can purchase that creates perfect score lines because it holds the bottles in place. If you're making items for gifts, wedding centerpieces, are many, it is wise to get the device. If you're really handy, you could make your own jig, and the cost will go way down.
The KEY to success is a single score line and not multiple passes. Multiple passes is what creates jagged edges. The single score line is simple but don't be tempted to keep going around the bottle thinking that the deeper the line the easier the cut! That is not true since the single score line creates a perfect line.
You can find two cutters on Amazon.com. One is $99 the other only $35. You could also make your own jig with a regular $4 glass cutter ( I have seen some YouTube videos that show you how that's constructed). Even with the devices, the key to a smooth cut is one score only.
Once you make your score line, there's a better method to separate pieces than using the hammer that comes with the kits. Glass naturally stresses when heat and cold are applied to it. Have you ever had a mug make noises when you're pouring in hot water? Well, you've created thermal shock due to the change in temperature. So, once you score your glass bottle, you want that effect. Here's how:
I use a tea kettle to pour hot - close to boiling - water over my entire score line. Be sure to turn the bottle so hot water heats the entire score line. Then plunge your now warm bottle under cold running water or into a bucket of cold water. This creates thermal shock and you'll get an approximately 95% success rate for perfect clean lines with smooth edges. You might need to smooth the edges for a drinking glass with an Emery cloth, but it's quick as opposed to grinding after the other methods and you'll be happy with the lack of work and the beautiful clean cuts.
Once you cut your glass bottle - beer bottles are actually the most difficult because they are thinner glass - you can experiment with cut lines at different heights and angles, use different colored glass, and create beautiful candleholders, vase is, and drinking glasses. You can mount them on wooden boards, leave them is a centerpiece, or be creative and hang them using wire. They make great gifts, they create safe havens for tea lights and votives so that wind doesn't blow the fire around, and they look great in a casual outdoor setting.
If cutting is too challenging for you, you can always drill a single hole in the base with a special Diamond coated glass cutting bit ( eBay) to cut a hole in the base. I usually tilt my drillbits slightly just get a grip on the glass and then straighten it out as I go. I keep wetting the hole as I'm cutting so the bit and the glass don't get too hot. Once you have your hole, you can smooth the edges or find a plastic grommet to fill it. Then simply run string lights up through the hole and fill the inside of the bottle.
You can keep the label if you so desire, although I like to remove them by placing a paper towel with a paste of baking soda and vinegar over the label for about an hour; it should pull off clean but you may need a steel wool or Brillo to help you with the remaining adhesive. You can add your own labels or none at all. Hope these images give you inspiration.