Hello,
We have had our pellet boiler (which was previously an oil boiler) removed from the basement, and the cleaning of the room has begun. To remove all the dust, we washed the walls and floor with quite a bit of water and mild detergent, which shouldn't be a problem as it is concrete and hollow block. Now, the next day, it smells quite strong even though the door has been closed, it's hard to describe the scent but I guess it's a mix of concrete, oil, and coal. It's still a bit damp, which is not surprising.
We have now opened the door and a couple of windows, but the question is whether we can expect this smell for weeks? Perhaps we should install a dehumidifier?