Rub potatoes with olive oil and pierce with a fork.
Place in slow cooker.
Cover and cook on HIGH for 4 to 5 hours or LOW for 7 to 8 hours depending on quantity of potatoes and size of slow cooker or until internal temperature reaches at least 210°F.
Sprinkle with salt before serving.
Top with butter, sour cream, bacon, cheese and chives, if desired.