Reheating corn on the cob is really easy. Remove the foil. Put the corn on the cob on a microwavable-safe plate and microwave. Usually I'll microwave the corn (covered with a microwave plate cover) for a minute and 30 seconds. The corn gets warm and none of the kernels pop. This grilled corn on the cob tastes so good reheated. The flavors of the butter and salt are still there, so you don't need to add anything to it.