Wooden cutting boards can dry and crack if they're not oiled regularly. Oil also prevents the wood from absorbing stains and bacteria. Most food-safe oils do the job, though food-grade mineral oil is a traditional cutting board finish that doesn't go rancid. Vegetable oil is food-safe and convenient but can spoil over time. Olive oil, food-grade linseed oil (not painter's linseed oil) or coconut oil are other food-safe alternatives. Whichever you choose, you'll preserve and rejuvenate your cutting board if you give it a monthly oiling.
Wash the cutting board with soap and water. If the surface is heavily scarred or coated with food residue, use a butcher knife or metal scraper to clean it, then sand it with coarse sandpaper, finishing with fine sandpaper.
Pour a few oz of the oil you've chosen in a cup and set the cup in a bowl of hot water to warm it above room temperature.
Dip a soft cloth in the oil and rub it over the cutting board, applying the oil liberally, rubbing mostly with the grain. Let the oil soak in for four to six hours.
Wipe off any excess oil with a clean cloth.
If your cutting board is new and has never been oiled or you've sanded it thoroughly and stripped it of all its old oil, repeat the oiling procedure once a day for five days to saturate it fully.