I've never known anyone refuse to use tap water to wash an aeroplane
The Cessna POH is specific that tap water is recommended for washing the exterior. For the interior ( plastic trim, instrument panel, headliner, control knobs) a damp cloth is recommended, and includes the statement
Volatile substances such as gasoline, benzine, alcohol, acetone, fire extinguisher or anti ice fluid, lacquer thinner or glass cleaner must never be used to clean the plastic since they soften and craze the plastic.
That statement seems to have been proven correct. The POH includes care of upholstery, leather, windscreen etc