Preheat oven to 350 degrees F. Scrub potatoes.
Dry potatoes with a kitchen cloth. Rub oil onto potatoes then sprinkle evenly with salt.
Pierce with a paring knife or fork all over potatoes.
Place on baking sheet. Bake at 350 degrees F for an hour or hour and a half depending on size of potatoes.
Potatoes are done baking when a paring knife inserted into thickest part of the potato slides out without much resistance.
Serve with butter and sour cream. Sprinkle with black pepper if desired.