Wash wooden boards with a bit of soap, rinse in hot water, wipe clean, and allow to dry upright. For board maintenance: every few weeks generously sprinkle coarse salt over the surface of the board, rub it with a sliced lemon, then rinse well with hot water. If your cutting boards are made from butcher block, once a month apply a small amount of mineral oil or beeswax, rubbing with a lint-free cloth in the direction of the wood grain. (Walnut oil, almond oil, and pure tung oil are good alternatives, but stay away from olive or vegetable oils, as they turn rancid quickly.) Reapply until the wood stops absorbing the oil. Wipe off excess and dry board overnight.
There is much conflicting information regarding which oils and substances are appropriate for use to safely maintain cutting boards or butcher blocks. This following list will help identify which products you should use to both sanitize and keep your board looking beautiful for years to come.