Technically, water is a non-flammable solvent (well, except in the presence of pure alkali metals like sodium, potassium, lithium, etc.). Not a very good choice here though. Except for the brake parts cleaner, most non-flammable solvents seem to work about as effectively as water. So I wouldn't let that drive the decision on what to use, unless you don't think you can be trusted with flammable solvents. Kerosene works pretty well too, is cheap and abundant, and not as dangerous as gasoline. I keep a can of original formula Gunk Engine Cleaner around for little jobs... added benefit is you can flush the part completely clean of solvent with running water (due to the emulsifiers) and let it dry completely, whereas most other petroleum-based products are just like... well... mixing oil & water.
