This will open up the pod so the moist seeds, often called the “caviar” of the bean can season the dish you are cooking. In vanilla bean ice cream you see these little specks which are the seeds.
You can use the vanilla bean over and over again until the flavor is exhausted. Simply wash it off and let it dry. I will keep the beans in a fifth of vodka in a batch of vanilla extract I am making, pull them out to use a little when I need them for cooking and then wash them off clean and dry and put them back into the vodka.
Keep the pod after you use the insides as there is a lot of flavor left. You can put it in vodka or brandy to make your vanilla extract or you can grind it up in a food processor with sugar to make vanilla sugar. I will use 1 vanilla bean husk for ½ cup sugar.
To make a batch of vanilla coffee you can put the bean in the pot as it is brewing. If you just want to make a cup of vanilla coffee you can snip off an inch or so of the vanilla bean and put it right into your cup to get a nice vanilla blast of flavor.
Don't throw out dry or withered beans. They will probably rehydrate in vodka or even warm cream and will still contain flavor. I don't recommend attempting to cut open very dry beans until they are rehydrated, as it's easy to have the knife slip. If you prefer, grind them up and use them in a recipe that calls for ground beans.