Microwave or toaster? How about a skillet with a lid?
They say one of true tests of a great pizza is how well it tastes the next day when it is reheated. The best method for reheating that special slice is to recreate the heating properties of a mini brick oven such as a hot skillet with a lid. The bottom of the pan is hot enough to re-crisp the pizza and the lid on top traps the heat to melt the cheese. Since we are using the direct heat of the skillet it will be ready much quicker than a toaster. When done use a quick wipe of the skillet to clean.