What should we do with very old Qur'ans endowed to the mosque, and similarly, with worn-out endowed carpets?

If the Qur'ans are still usable, they should remain in the mosque. If they are no longer usable, they can be burned or buried in a respectful place. As for worn-out carpets, if they can still be used, even in another mosque or its annexes, they should be utilized. If they cannot be used, they should be removed from the mosque and disposed of far away from it.