Citadel Typhus Corrosion is an engineering paint and is designed to give a really oily, greasy, dirty look that real used machines have.

Shake the paint well before using it. It's a lot like a wash or shade and it's very, very thin, but there's one key difference and you'll notice it as soon as you put it on a pallet. The paint is actually very grainy, because of the little bits of texture. So when this dries on the model it gets a really nice textured effect.

Remember that when using this paint, the application technique for it is quite rough. It is best to use an older brush when painting on the model and make sure it gets into every nook and cranny. If you put too much on it, wipe it off. Wipe it down and it will look particularly good because it will appear as if water is coming out.