As a quick test, I decided to try out a new technique on this M41A1 (Tamiya 1973) 1/35 kit. Method is to undercoat black, then paint on a layer of silver, followed by a layer of Mig Dark Rust pigment. Then the Olive Drab is airbrushed over the top and left to dry. A small file is then rubbed over the surface to produce the silver and rust effect. More to do before I decide if its worked.