Apply a generous coat of mineral oil (butcher block oil, boo's block oil), allow the oil to soak in for several hours, then wipe off excess with a soft cloth. This can be done once a year or more often depending on use. Please remember that all oily rags pose a fire hazard and must be disposed of properly (immediately spread out outdoors to dry, then thrown away in an outdoor trash can).
Clean with a damp, wrung out cloth with warm water with a small amount of dish detergent. Wipe dry ensuring that no water is left on the item. Pledge furniture cleaning spray can also be used.