I’ll keep this short and sweet for the washing part and explain more in detail for the oiling process.
Just a forewarning: Wood will always move but, these steps will help prevent and/or prolong it from doing so.
Boards should never be put in the dishwasher.
Hand wash with warm water and soap on both sides. This will keep the moisture level even within the wood.
Towel dry and leave to dry leaning up against something for maximum air flow.
You can use whatever food grade oils/waxes you prefer but I’ll post the ones I use below.
You can treat your cutting board as much as you’d like. The more you do the better it looks and longer it’ll last. But, a good rule of thumb is when it looks dull it needs oil.
If you just want to touch it up or bring back the sheen then just add either a wood conditioner or mineral oil. I personally use a wood conditioner because my boards already come heavily oiled and the wood conditioner provides a longer last (made with mineral oil and some type of wax).
Using a wood conditioner – apply, rub in, let sit for 20+ minutes then, wipe dry. Let it sit over night for it to cure/harden.
Using a mineral oil – apply, let it sit for 20+ minutes (no need to rub in) then, wipe dry. May be used after application.
For More Intense Care:
Just use enough to coat the wood and let it sit for at least 20 minutes (no need to rub it in, just make sure the cutting board is wet all over). If the board soaks up the oil (it won’t look as wet), apply more oil and let sit again. Repeat as many times, if needed. Wipe off any excess.
For additional protection you can use a conditioner/cream (made of mineral oil and bees wax) after the mineral oil application. Rub it into the board and let sit for at least 20 min. This will help keep the moisture in the wood. Then, wipe off any excess.
Products I use: