Slice pods in half and scrape out seeds into bottle of Rum. Add the rest of the pod to the bottle of Rum. Shake twice a day for a week. Lasts forever. Shake before use. If you get a bottle of rum with a cute label you can display it out on your kitchen counter.
I use about 1 1/2 vanilla pods per cup of rum. You can judge the size bottle of rum you have to how many vanilla pods to add. It doesn't matter if you use light or dark alcohol the vanilla pods soaking in the liquid will turn it brown. You can use vodka if you like, personal preference.
When I use half of my bottle I add more rum to fill it up and can do this several times before I add new vanilla pods.