Sand or wire brush the rudder/propeller?

[serpa4]

My boat was purchased used. It used to have growth on it, but was scraped off by the previous owner.
It is still rough though and "looks" ugly with lots of grit on it.
Should I wire brush it to make it smooth and shiny or should I sand it smooth?
If I should sand it, what grit?
Thanks.

 

[knotflying]

Wire brush, then sand with course sandpaper. Wash it down to remove any residue. After it id dry wipe with acetone. Then apply running gear paint, or Pettit barnacle barrier or, as I use, cold galvanized paint.