I've definitely noticed differences in different cans of naphtha. I've even seen it come out green and cloudy from the can, albeit that batch was probably quite old, 20-30 years.
I know the fumes are toxic of course, but it can smell differently, not that that's indicative of quality difference.
Some naphtha has been seen to work differently than others in the past, one brand I remember smells very strongly and much more unpleasant, like it wasn't as 'clean' as other brands smelled, and it worked poorly, only yielding small amounts of wax that it took days to weeks to fully evaporate from.
Different distributors have different petrochemical makeups sold as 'naphtha'; typically VM&P (varnish maker+painter's) is regarded as the preferable 'blend' but this can be arbitrary as well.
I've also read something about 'light aliphatic naphtha blends' working best, there is some research to be done on the topic if one is uninformed and interested in it.
MSDS sheets may be found and the exact contents can be known.
... Until recent times actually, 'naphtha' was loosely defined in terms of petrochemical makeup.
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