My mother in law supplies me with GU. Every time she visits she brings me 20-30 packets. It's pretty nice of her. She has been doing it for 2-3 years. Anyway, she usually brings at least 5-10 chocolate ones and I have a huge backlog of GUs to consume. I've been finding that old chocolate GUs solidifies back into solid chocolate chunks. When they're past due, they become chocolate chip GUs. Other old GUs haven't been doing that, only chocolate outrage. Just a FYI from my vast mountain of GU experience.