Cut vanilla beans in half lengthwise with a sharp knife or kitchen scissors.
Use a funnel to fill your bottle 3/4 full with alcohol or glycerin.
Add 3-5 vanilla beans, halved, to every cup of alcohol or glycerin.
Top the bottle off with more alcohol or glycerin until the beans are submerged completely.
Close the bottle tightly and allow the vanilla to sit in a cool dark place for at least 3-6 months (the longer the better).
Decorate your bottle with your own label, raffia or ribbons. Keeps indefinitely.
The alcohol you choose does not have to be fancy or expensive at all. It is simply a solvent to extract the vanilla goodness. The alcohol will evaporate off when you cook or bake with your vanilla anyway.