Heat grill to 350º. Prick potatoes on all sides with a fork.
Place the potatoes on a microwave-safe plate and microwave on medium power for 8 minutes. Let cool 1 minute, then rub the skins with oil and season with salt.
Wrap each potato separately in aluminum foil. Pierce the foil several times with a fork, then place on the grill. Close grill and cook for 45 minutes to 1 hour, until you can easily insert a fork through the foil into the center of a potato.
Remove potatoes from grill and let cool 2 minutes. Open packets and make a 3” deep vertical slice in the top of each potato. Use a spoon to widen the indentation. Top with cheese and other desired toppings, then serve.