It was a bit of messing about, but it was approximately this...
- Base coated it all red
- All over wash of agrax earthshade, reasonably light, heavy in the joints
- Edge highlight of orange, got bored of that and decided to make it "weathered"
- Stippled on some typhus corrosion - very very light, that stuff is thick and dirty
- Stippled on some kind of mid grey colour
- Stippled on some nurlge rot? light green dry paint
- Stippled on some ryza rust
- Used some acrylic matte medium to create a "base" to drag colour through for the streaks
- Used a bit of typhus corrosion again and dragged it upwards towards the thing I wanted to be streaky (large hole, rivets)
That was about it so far. The medium is important for the streaks as it allows you to correct and make it look natural without it drying on the base colour.