Don,
I've looked at this before, saved a link or two, but cannot give you any personal experience as I've never tried it yet. If you Google 'molasses rust removal' you will find tons of threads discussing the process. Here's one I saved that talks about three or four different methods, including electrolysis using a battery charger which is a bit unique. I had a tip a while back about rust removal I believe that the "attack on machined surfaces" is simply the removal of rust on those surfaces, leaving pitting behind as Pat described, and I would think that any method used is going to result in the same surface roughness - machined surfaces rust, and when the rust is removed the formerly smooth surface is now rough.