It is immediately obvious that you know nothing of organic chemistry: "some sort of mineral spirit, I prefer naptha." The two are different chemicals that happen to have similar effects on some materials. In point of fact, "naptha" has several meanings, none of them precise, and different in differing parts of the world.
We are talking about the grease and oils used in bicycle construction and maintenance.
It isn't that complicated.
Naphtha or mineral spirits both do a fine job on the stuff
we are talking about.
No matter what the grease an oil has turned into or has in it, naphtha will remove it.
And yes, naphtha is rather benign as such things go and quite safe to handle.
This is what I do. I know what works.