You can put 木砧板 into the bleach. It may works, but I haven't experiment for it.
Or the most easy way is to buy another one in a trustable shop such as:
PriceRite and IKEA or other shop that is suggested by others to you.
You can also try to use some lemons and squice the lemon juice out and wash
it with the lemon juice, it may works.
(I'm only guessing, I am not responsible for any matter that cause inconvience
to you)
Because most smell can be cleared by using bleach or lemon juice.