I've considered treating it with a rust remover as suggested there, but never contemplated the knotted wire brush.
I've sanded a couple area's pretty good, and I've still got pits. it is not close to rusting through, but I'm going to have to get that metal pretty thin to get it all out, and it will take quite a bit of time. I've gone over it with the brush on my die grinder pretty good, but those things have limits.
