I am thinking about getting some Mega-Steam fluid. From what I read it smokes a lot better than the others and comes in a lot of scents. I have an oil fired steamer, a coal fired steamer, a couple of turbines and some diesels with smoke units. I am not looking to get crazy prototypical and get specific scents for each type of loco. Yet. Is there a really significant difference in the scents of the oil-fired, coal-fired, Big-Boy and diesel scents? Looking to get one or two scents to try it out. Thoughts and opinions on the scents would be appreciated. How does the cleaning fluid work? Do you just put it in and run it until it stops smoking then add a new scent?