Meat and vegetables should not be cut on the same cutting board. There should be a separate cutting board for raw meat.
Wooden cutting board should not be soaked in water or washed in washing machine. The result will be cracks in the item or spoiled shape.
Cutting board must be washed in the old-fashioned way with sponge and washing-liquid.
Cutting board must be treated with oil from time to time. Oil will make the wood more water-proof and it will also dry faster (more hygienic).
Oil will make the wood also more resistant to cuts.
It is not suggested to use ordinary vegetable cooking oil (olive, sunflower, corn, walnut, peanut, sesame etc.) for treating the cutting board, because of rancidity. After a while your cutting board will smell and have unpleasant taste. As a cutting board is in contact with food, oils that can tun rancid should be avoided.
There are different options to treat your cutting board with. In general, we can say that beeswax, Coconut Oil (Re-fractioned), food-safe Mineral oil (sometimes called liquid paraffin) and dedicated oils for treating cutting boards are good choices. The final decision is up to the user’s "taste".
First - let the cutting board dry completely. At least 24 hours would be the best. Now oil the cutting board thoroughly. It is really comfortable to use kitchen paper for it. Let it absorb for few hours. Now wipe off unabsorbed oil with dry kitchen paper.
If your cutting board has served you so much that there are lots of cutting marks on it, it would be good to sand a little bit with very fine sandpaper. By doing this, you will remove old oil remains as well as food remains that are absorbed into the cutting board surface. Also, your cutting board will be more hygienic now. It is really important to treat your cutting board properly with oil after sanding.