

They aren’t the cheapest, but I really like using GripStics to reseal bags. As long as the bag is not made of a very thick material, you can get an airtight seal (Eg, good for plastic-y foiled bags, not so good for a bag of flour made out of paper). There’s no mechanical movement at all, so they’ll never break.
https://medievalbritain.com/type/medieval-life/clothing/medieval-trousers/