If I was feeling especially paranoid, I would probably hurl the thing into a cauldron of molten lava
The device cannot be truly destroyed by any means we currently possess. The flames of an ancient wyrm could perhaps unmake it, but such dragons are not to be found in these parts. I suggest gathering a fellowship to carry the tablet to the mountain Amon Amarth, in the dark pits of the land of Mordor, and cast it into the fires of Mt. Doom in which it was forged. Only then can we be sure that it is unmade, completely and utterly, and will trouble us no longer.