I masked the black undercoat in several areas to create a natural chipping effect. Then I scuffed up the armor using a wire brush and a bit of sandpaper, and added some deeper scratches with a metal file.
For the weathering, I made my own Mimban mud using a mix of acrylic grey paint, real sand, and Fuller’s earth. I applied it with different brushes and sponges, mostly using a dabbing technique to build up the texture.
Finally, I finished it off with some pastels mixed with water to bring out the finer details and add variation to the grime.
Some pics of how it ended up: