Preheat the oven to 400 degrees F. Toss the puffed rice, puffed wheat, Chex, puffed millet, oats and coconut on a large rimmed baking sheet. Bake 5 minutes.
Meanwhile, melt the butter in a small saucepan over medium heat. Stir in the honey, cinnamon and salt.
Pour the butter mixture over the cereal mixture and gently stir with a rubber spatula. Return to the oven; bake until golden brown, 3 to 5 minutes. Let cool completely; store in an airtight container.