The Vallejo kit comes with brown iron oxide pigment, you'll see some piled up to the left of the terminal. I love the 3D effect the pigment provides, but the stuff is messy as heck to work with, leaving stains all over my hands and everything else I come in contact with. I need to think of a better way to apply the stuff; right now, I'm just trying to dump small amounts from the bottle and use the brush to spread it around, which works to an extent, but it's a bit haphazard and I feel like I should have more control.
Jeff recently sent me some excellent tips that I'll apply in future models. I have a bit of backlog to share so better models may not turn up on the blog for a while, but I definitely feel like my improvement has stalled a bit. But I'm excited for what's ahead!