Personally I'd be very careful with the "steam" room approach. The idea with filling the room with steam (water droplets, actually - steam is the invisible *gas* state of water above boiling point) is that it scrubs the air in the room of any dust, which falls to the floor as the droplets settle. That is certainly well and good in principle.
However, a word of caution - if your camera is cooler than the air in the bathroom you may well find (even slight) condensation forming on your camera. On the outside of the body that will do no harm. But if you remove the lens and expose the sensor you then run the risk of having water droplets condense on your sensor. There, they will mix with any dust that is present and potentially create a nice sticky porridge that will be far harder to remove than the original dry dust. I don't speak from experience here, just instinct and my idea of common sense.
I just do my sensor cleaning in the dining room, which is closed off (doors and windows) most of the time as it gets very little use. There is therefore pretty much no airborne dust in that room.