My humidor smells like *&#@

[T.G]

I've seen some solid wood ACID boxes that will still have the smell years after being emptied.

You can try airing it out, or putting a box of baking soda or a carbon pack in it and closing it up, see if that helps. If you sand it, don't sand too deeply, most inexpensive smaller humidors are just a very thin sc veneer over MDF.