Wash potatoes with a brush. Dry with a paper towel.
Rub each potato with oil and place on a baking tray. Coat each potato with salt.
Cook for 45 - 60 minutes (smaller potatoes will cook faster). Check the potatoes with a fork - it should insert easily. If not, continue cooking in 5-minute increments and check again. Here's a guide for cooking times for baked potatoes.