When dry, I gave all of the castings a thick, wet, dirty wash of black/brown. Again, let dry.
Finally I dry brushed all of the castings with some very light brown that I made by mixing a little flat white & brown acrylic paint. I used a flat, wide brush & just sort of hit the high points on the castings to make the details pop out. I added a couple labels and they're ready to add to a layout.