Fill a medium sized pot or small crockpot 3/4 full of water, and add the ingredients of your choice (recipes below).
Bring to a boil for a few minutes, and then lower the heat to simmer.
Let it simmer for as long as you'd like. Be sure to watch the water level, and refill if needed.
Save the mixture in a glass jar or bowl in the refrigerator when finished. It can last you several days! Simply reheat the next day to re-scent your home.