Forget the Sharpie, you need a full archeology team for that cabinet. I bet there's stuff in there older than some of the interns. My system is just a yearly purge where I throw out anything that looks like it witnessed a major world event. Tea from 2021 is basically a historical artifact now. It's not a pantry, it's a time capsule.
Ever think tea was basically immortal? I found some ancient packets at my parents' house and it tasted like dust. Now I just write the month and year on everything with a sharpie when it comes in.