From cutting up fruits and vegetables to meats, your wood cutting board sees a lot of action. Each piece of food leaves its odor on the cutting board's surface. Onions especially leave an odor that easily transfers to other food items. If left on the board, the onion smell will only become stronger. Soap and water alone will not remove the onion smell. You need a substance that will penetrate the cutting board and neutralize the odor as well as remove it.
Sprinkle 1 cup of coarse salt or baking soda onto your wood cutting board. Use your fingers or a soft cloth or rag to rub the salt/baking soda into the board.
Let the salt or baking soda sit on the board's surface for 4 minutes. Wipe or shake the salt/baking soda from the board into a trash bag or can.
Wet a clean, soft cloth or rag with 3 tablespoons of lukewarm water from your sink. Wring out excess water from the cloth or rag and wipe the cutting board clean with the damp cloth or rag. Dry the cutting board with a clean cloth or rag.
Apply 3 tablespoons of an USP-grade mineral oil to a soft cloth or rag. Rub your wood cutting board with the oil-soaked cloth or rag to reseason the board. Let the board dry before storing it in a cupboard or other location.