Brush iron and rinse off.

ANY other way will result in corner splash.When you  get soft spots there it usually runs under the tub. 

get it really clean and wire brush it or use some kind of chemical to lighten/brighten it?

Awesome stuff, very easy to roll or brush on with no streaks.

You can dramatically change a bathroom by going from brushed nickel to oil rubbed bronze or like the picture in your example, gold to any other finish easily later on.Some ideas I personally have done and love:Heated floors.  

I would think I need a soft close as this is a $150K house in an A area. 

Cabinets can be especially difficult as the different grains in the wood and the frames themselves can make the brush marks stand out.

Brooks: 'What goes in hard and pink then comes out soft and sticky?'

Wouldn't fly with the MRS since everything else was brushed nickel.

I subtracted soft costs, etc. for this analysis.