Great effect
Just used this for the first time, and am impressed with the results. The engine grime worked well on a twin wasp radial, making the engine look well used and weathered. I used the engine oil to create oil streaks on the fuselage where oil might have escaped the cowl. The color is spot on. Finally, I used the kerosene stain to simulate fuel spills from the external fuel tanks. It was very convincing as well.
