I have a bare block here that has been sitting for some time.... it has some VERY VERY slight signs of surface rust on the bare metal parts...
like on the deck, and journals... it is almost like a powder or a dust... not real rust rust...
i dont even think it would show up in a photo... or i would post one....
but just curious what would be safe to clean these up without damage to the surfaces?

just a scotchbrite? (would that be enough to get it off well?)

fine sandpaper? (would this alter the surfaces?)

steel wool? wire wheel/brush?

If this was anything but an engine block it woudl be so slight i wouldnt even care or notice... but i just want to be safe.

I would use some brake cleaner on a rag myself.You could use some super fine sand paper which would merly clean that light coat off and not harm the parts.Bc it's exposed to air and moisture causes this and nothing to fret over.I myself have my eng exposed no oil pan or valve cover and in the process of repainting my block and doing some gaskets using high temp eng paint and high temp primer.That was unrelated but understand what u are inquiring about.The advantage to the brake clean is it evaporates and will remove the stuff u decribed.Hope this helps.

See i think it may be a lil deeper than just "dust" but it looks like rust dust...

ya know how if you are sandblasting, and get down to bare metal, and the blaster coughs and sneezes a spritz of moisture onto the metal how you instantly get a little orange spot...

well that is what i have in a few spots as well... the SURFACE of the metal is all fine... just enough of a dusting of dust to worry me...

I did get some photos... i will post the soon.

U are fine and using the brake cleaner will remove that layer u are talking about.I thought about it and my suggestion will work.With my crank and valves exposed they have a dry appearance mainly bc it's in my garage but,using a rag with brake clean will remove that light layer.I would only sand if it does not remove it but,feel it would not hurt it being the oil once put together complete would take care of that anyway.

I would avoid sandpaper, but consider trying VERY fine steel wool if necessary. If you're not using it at this time, I would just give it a very light coating of engine oil with a paintbrush to help prevent it from continuing. The oil will seal the surface from the air and displace any moisture present in the pores. Later, the use of brake cleaner will easily take off this film of oil and then you could use the steel wool if necessary.
John