You can absolutely freeze your Oreos if you have too many and want to save them. After all, you cannot eat them all in one sitting. They will stay fresh in the package at room temperature for weeks but once you open them, they can get stale pretty fast even when using that new resealable packaging. One way to save them is to freeze them. Just flash-freeze them on a cookie sheet and then layer them in a freezer-safe container with parchment or wax paper between them.