Heat your oven to 170-200°F and place finished waffles in a single layer on an oven-safe wire cooling rack on a baking sheet to keep them warm while you cook the rest of your batter. Using a wire rack helps air to circulate all the way around the waffles, keeping them nice and crispy. Continue to transfer cooked waffles from the waffle maker to the wire rack and store in the warm oven. There is no need to cover your waffles while they are in the oven.