Oh, I should have mentioned that (according to, IIRC, the children's book cited in https://news.ycombinator.com/item?id=44495658 https://news.ycombinator.com/it

Oh, I should have mentioned that (according to, IIRC, the children's book cited in https://news.ycombinator.com/item?id=44495658 https://news.ycombinator.com/item?id=44495658) some glucose oxidase remains in the honey, and when enough water gets into the honey for it to become active, it produces more hydrogen peroxide at that point. So the peroxide itself doesn't have to remain stable for centuries.