Distillation is a process that you can use if you need to be sure that your drinking water is pure, or if you want to separate components of a liquid. You might be familiar with the idea of homemade stills that are built to make alcohol, but distilling alcohol, according to Monster Guide, is illegal in most countries, including the United States (the exceptions are Italy, Austria and New Zealand). You can build your own small still out of simple materials that you may already have around the house.