Spitfire aircraft use Merlin engines, which have similar problems to most engines during standby, where corrosive exhaust gasses effect internal component and then require more frequent expensive maintenance works. Other aircrafts such as Mustangs and Kitty Hawks also use a Merlin engine.
Bernd (Bernie) Heuser Chief Engineer of The Old Aeroplane Company and National Air Museum found, by purging with dry air using DST model DC050 after running the engine, the pollutants are substantially displaced, and remaining compounds are made less corrosive with low humidity air. Otherwise, ambient humidity is contained within the engine and due to the thermal inertia, condensation can even form (see example).
Corrosion typically requires four components to implement the corrosive circuit. These are the anode (the positively charger material), the cathode (the part which corrodes), the electrolyte (typically water or water vapour) and air for completion of the circuit. The elimination of any of these contributions will halt the development of corrosion.