I've used Naval Jelly before on old rusted blades... The results were very similar to that explained for the Evapo-Rust. It is an acid degradation of the blade as well.
http://www.shorechemical.com/Section...aval_jelly.htm
You do have to polish the plade afterwards and the pitting is still present.
The best way to work out the rust and pitting is to regrind, or sand the surface.... Which takes a LOT longer.....
C utz