I have engraved private keys onto titanium plates for exactly this purpose. They are kept in a box with the other valuables, like a hoard of POGs, various tamagochi, Princess Di beanie baby, and some very rare and powerful Magic: The Gathering cards. Dang kids are gonna be floored when they find this box next to my partially decomposed earthly remains.
lol, full bullet proof . I b t it won't get stolen. Congratulations for having such a brilliant idea and future for generations after you.
The question is very interesting and it can be interpreted in two ways. Or from children to save bitcoin, or for children. But if children today with a computer on you, then hiding the crypto currency will be difficult.