Underlined comments are confusing. Turpentine is not a mineral solvent. It is made from wood (http://en.wikipedia.org/wiki/Turpentine). Apparently, according to the Wikipedia article, "mineral turpentine" is a term used in some locals for mineral-solvent based thinners. The mineral solvents I mentioned are largely aliphatic hydrocarbons (Stoddard has a up to 25% aromatic hydrocarbons, http://en.wikipedia.org/wiki/Stoddard_solvent) which have good grease cutting capability and poor solvent strength, even for shellac. The term "spirit" generally means the solvent was easily distilled and would have a lower boiling point than something like kerosene..Windings are lacquered in shellac on older motors and polyurethanes on newer motors. Don't use alcohol, or mineral solvents like turpentine or thinners or anything that says "spirits".
Hot soapy water is good, and kerosine type solvents like WD40 or auto degreaser should be ok. Some auto degreasers these days use detergents and not solvents, they should also be fine.
Coating? Do you mean the wire coating, if it's exposed to liquid water while under use?...the coating cracks with repeatede heating/cooling cycles...
But turps will hurt polyurethane lacquer if the motor has more modern lacquer. And it's not nice to paint....
Turpentine has slightly greater solvent strength than the hydrocarbons I mentioned, but its solvent strength compared to alcohol (ethanol) is considerably less. Turpentine cannot be used as a solvent for shellac, whereas alcohol is used for that.
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