Well, not completely empty. When you get to the point that you can’t scrape an appreciable amount from the jar, they make great dog entertainment. I had to hold onto my mostly empty jar (plastic, I don’t give the dogs glass jars) until I had two, since we have two dogs. Missy thought these were the best thing ever! Griffin loves them too, but he needed to have protection from the puppy so he could enjoy his treat. Watching the puppy try to get her tongue to the peanut butter at bottom was worth the wait!