I've restored a few planes and I try to make them look like they came
out of the tool box of a mechanic who used and cared for his tools.
Shiney, showroom new isn't really approriate. On rusted surfaces, I
use a solid rubber block with grit embedded, Sandflex is the name from
Woodcraft (and others)
(http://www.woodcraft.com/family.aspx?familyids29 ). I can control
just how much "patina" I want to see. It doesn't leave black mess like
sandpaper. You can look up electrolysis, but it is messy process, and
leaves you with a gray steel. It does cut the red rust, not the black
To work properly, the mating surfaces on the frog and body need to be
resonably smooth. The top of the frog needs to be reasonably smooth so
that the cutter blade will slide smoothly when adjusted. Once you've
done that, any further smoothing is for aesthetics.
So, to answer your question, the scotchbrite won't hurt anything, but
be sure that you will be happy with the appearance of the surface it
leaves. After cutting down to fresh steel, I would definately protect
the metal with paste wax. I use Johnson's.
And, if the black paint "japanning" on the inside of the body is a bit
rough, you can make it look a bit better by waxing the first coat with
liquid black shoe polish.
Do clean up the wood handles too, when that rosewood is finished and
shining--looks great. Wax helps them too.
To use the plane, the blade must be razor sharp at the proper angle.
Again you can find help on this courtesy of Google.