Here, I went and laid down a thick black Magic Wash. One note here is that before I laid down any washes, I sealed the mini with a thin matte layer to stop the wash from picking up the metal paint. Also, from this point on, changes in color may be real subtle - so I actually skipped a few photos because the change doesn't show. I will still describe all steps.
My next step was to lay down a drybrush of the original base layer of Steel. Then a second, thinner Magic Wash was applied.
The next layer was a wash of Badger Model Flex Rust (16-172). This was a real thinned wash - about 5-to-one on the water. You will notice how it settled toward the bottom on the legs of the mech, just what I was going after.
Now, I went and painted all areas that I wanted a different metallic color on, with flat black. This is also where I pulled out the Dremel and added the dents and battle damage.