An old recipe that says “use the blue bowl” makes sense to exactly one family. Legacy is often that specific.

Very little of what gets handed down is general wisdom. It is the blue bowl, a particular chair, the phrase only your family uses, none of which would mean anything to a stranger reading the card. That narrowness is not a flaw. It is what makes an inheritance recognisably yours instead of advice that could belong to anybody.

Keep one of your family’s odd specifics on purpose: use the phrase, keep the bowl, make the thing exactly the strange way it gets made. Then ask where one of them came from. Somebody probably still knows.