rust converter; snake oil?

A couple of years ago, I spread ice melt off the back of my rancher. Then I spent a few hours, every day for a few days, plowing 20 something inches off 200 yards of concrete. Then I parked the quad in the garage till the spring clean. Sometime that summer, I noticed a brown crust on the rear diff and axle housing. Oooops!

So now I'm ready to deal with it. I have a wet blaster to try out and a hand held sandblaster if it just sucks. I have wire brushes and flapper wheels and I will remove all traces of rotting metal, but then? Then comes the refinishing.

Anyone ever have anything resembling success with anything resembling this product?