Spread cereals on a baking sheet, and toss with butter-salt mixture. Bake 30 minutes, stirring once halfway through. Once fully baked, stir mix once more, and sprinkle cheese evenly over mix. Place back in oven, and allow cheese to melt, 3 to 5 minutes. Watch cheese carefully, ensuring mix does not burn. Remove from oven, and let cool and harden, 5 to 10 minutes.