It's not essential to cool your geckos, but if you want to it goes something like this: drop the temperature gradually over the course of a few days without feeding them. You could just eventually turn the heat off and let it be room temp; I've decided to keep it at about 70. Continue to provide water but not food for about 6 weeks. If you start, you'll be ready to warm them up by mid to late Jan. which is just about right.