Either boil or bake the wood whatever you do, and removing the bark might be a good idea to make sure you can get it as clean as possible.
The only thing I'd like to add is not to make it too high of the floor of the enclosure because although the snake is likely to climb, ball pythons are pretty clumsy little climbers, so you don't want them to have too far to fall. maybe about five-seven inches is what I'd aim for.