Useful for filling in small gaps in models.
This is a great, general way of doing weathering effects. Works on anything!
This is a great way to provide weathering effects on armor, tanks etc. Note that the choice of second paint is based on the model you are painting, the Calgar Blue here is just an example. This second color should be your highlight color for the specific model.
Even though this is for an Orruk model, this same pattern could be effectively used for many Greenskin models.