Red Green writes:

You could also use naptha paint thinner. Essentially the same stuff.

It's exactly the same as naptha. Look at the contents of a container of
lighter fluid - Contents: naptha.

Yeah, but not all naptha is the same chemically. Naptha isn't a single
pure substance; it's a soup of several different hydrocarbons that all
have relatively low boiling points, and come off the distillation column
in the refinery near each other. If you're just going to burn it, it's
probably all pretty much equivalent, but if you're using it as a
solvent, you may care what it is chemically.

My own experience is that "lighter fluid" naptha and "paint thinner"
naptha are both pretty good are removing the adhesive from sticky
labels, while not attacking most plastics (at least over the span of a
minute or so). While "camping fuel" naptha is a lot more aggressive at
dissolving some plastics; I don't recommend it for sticky labels.

When I'm doing something particularly sensitive to contamination, like
cleaning gunk off a lens when water plus detergent (lens cleaner) and
alcohol won't touch it, I tend to use Ronsonol lighter fluid. It
evaporates with no residue.

You can often buy Xylene from the same shelves as generic "paint
thinner", and that's a well-defined single chemical compound no matter
who makes it. But it's a pretty strong solvent, and has a strong smell
too, so I avoid it when I can.

Dave