Wash and dry the potatoes and then rub them with oil, salt and pepper. Individually wrap them in foil.
Put them in the slow cooker and cook on high for 5 hours or low for 8 hours.
When the potatoes have been washed, used kitchen paper to wipe them dry.
When putting your foil wrapped potatoes in the slow cooker, the part that has the extra foil bunched up should be the part that touches the bottom of the slow cooker. This will help them not to burn.
Make sure that the slow cooker isn't overcrowded. The potatoes shouldn't be laying on top of each other, and each potato should be touching the bottom of the slow cooker bowl - this helps them to get crispy.
If you do want to give your potatoes a little extra browning/crispiness, then turn them over half way through cooking. This isn't essential though. You can also skip the wrapping in foil step, and lay them on a couple of pieces of baking paper in the slow cooker.