So, early tests have been performed, in order to find the best way to apply these products, on.. my kitchen sink
This sink is nearly as old as the delorean, so it's a good benchmark
Both products should be applied on a cloth, and not directly on the steel surface.
I started first with BKF: it's a white powder (...) with light abrasive and degreasing agents. It removes the dirt laying on the steel, nearly without polishing and without leaving marks. If you take a look at the cloth at the end of the process, you can see the abrasive effects: light black marks will be there, but no as strong as with the dodo.
In any case, you need to rinse the surface after having applied the bkf.
The surface is more matt than with the dodo, so teh abrasive effects are lighter.
In my opinion, the bottle should be provided with a filter on the weighing hole since it's very hard to perform a proper weighing: the risk to overweigh is concrete.
I skipped this area during the cleaning process:
Now, my mother is very happy because the sink has never been so shining
Steel kleen, on the opposite side, is competely different: it's a watery liquid in a gas-free spray bottle. It seems that it doesn't contain abrasives, since it doesn't leave black residus on the cloth.
Its behaviour is similar to WD40: it cleans and at first it leaves a slightly greasy film, but then absolutely undetectable when it's dry. You don't need to rinse the surface.
So, if you wait some minutes after having applied the products and then you touch the surface with your fingers, no fingerprints will be there!