This can be done by microwaving at the lowest power for an hour. The corn on cob demands to be checked and rotated after every 5 mins. You can also choose to use a dehydrator overnight. Corn on cob can also be dried in an oven. You need to heat it at 200°F leaving the door slightly ajar. This will take 4-6 hrs and you should rotate the cob after every 1 hr so that it's evenly heated throughout.