Rinse and scrub 8 sweet potatoes. Without drying them, place them into the bottom of an extra-large slow cooker. Cover, and cook on low for 6–7 hours.
OVEN:
Preheat oven to 425°. Rinse, scrub and dry 8 sweet potatoes. Prick sweet potatoes a few times with a fork or knife and place on a foil-covered baking sheet. Bake 45–50 minutes.