What's really resourceful, however, is using the empty vanilla beans/pods to make vanilla extract. Even though you no longer have a plump bean full of seeds, the pod still has plenty of flavor that alcohol can extract. In my vanilla extract tutorial, I recommend waiting at least 6 months before using. But now that your vanilla bean pods are practically empty, you may want to wait closer to 12 months before using so that optimal flavor is reached. Reuse the empty beans/pod right after you scrape the seeds out of them. If you submerge them into the sugar, then use all your sugar, the empty beans/pods will have sugar all over them. If you want to use those, you'll have to rinse them with water and wait for them to dry completely before using for extract. Some flavor may be lost during this process. I haven't tried reusing beans that were used for vanilla extract to make vanilla sugar. If you try it, make sure the beans are completely dry. Some flavor will be lost since the bean(s) was/were extracted. Source: sallysbakingaddiction.com