After nearly ruining a model when I oversprayed it with Tamiya flat base (I mistakenly thought it was a clear flat), I noticed that the very appearance of the dried base looked surprisingly similar to what I had seen in actual aircraft exhaust stains. Airbrushed sparingly on top of the regular black/brown exhaust stain and close to the exhaust stacks, the flat base dries into a convincing representation of a “lean” fuel-mixture discoloration along the fuselage. I have compared it with the stains on my own 1998 ACA Scout airplane, and dang if it does not look like the real thing. (By the way, I clean that muck off every time I am finished flying!)
Tip submitted by:Woodrow AnselenCorona, Calif.