Thanks, this was informative, I sincerely had no idea (I do not even own a car, never did, and do not understand much of cars. No I do not play with Barbie, I just am not interested in cars and motors that much

But I like Audi eventually!)
The video is funny.
@Nap: I have reread your last post and got scared about my coming soon Black Oxide Surge rusting. I was about to write to stop the order (not yet shipped) and switch to Polished.
I have then researched a bit and found no evidence that the Black Oxide would rust more easier.
But I have understood following things:
1) high polished steel rust less
2) bead blasting can rust more
I suppose this means that the high polishing makes the metal less porous, no way for the rust to get it. A bit like plants, some fertilizers (like K and Mg) make their cells harder and can help preventing Fungi to get in.
So I am also supposing that in order to apply the Black Oxide finishing, the tool must not be high polished (after all, the black oxide is a form of controlled rust, so to say).
I think that till the black oxide is there, and supposing is well made and uniform, no rust will appear. But when the black oxide will wear out it will leave NOT POLISHED spots of metal free.
It is possible that those parts rust, because they are less polished (if at all) than the polished version.
I would like to know what are you guys your though about this.
I anyway understand that a good care and maintenance will prevent rust.
Which oil or other product do you use to prevent rust?
I understand that WD40 is not that good at that?
Cheers