Oil of Wintergreen was an old timey trick. And yes, it's supposed to be a very deadly poison. I'm not sure if it's one of the ones you shouldn't even get on your skin and that might depend on what it's distilled into- alcohol, a petroleum based substance, water, natural oils, etc. My wife had some mint oil tincture I think she made that if you got it on you finger tip, just a drop and wiped it right off, you'd taste the mint within a minute or so in your mouth. Some of that stuff is nothing to play with, even if you mouth does taste minty fresh!
ATF was reputed to be what Singer Sewing Machine Oil was, more or less. That was another old timey "secret". Marvel Mystery Oil was also supposed to be heavy on ATF. Seafoam and several other carb cleaners are allegedly heavy on acetone and something like benzine with some wood alcohol mixed in. Who knows? Some works, some doesn't. You can look at the MSDS and get a basic idea but what quantities of what substance are mixed in makes it what it is. The good smelling ingredient of Hoppes #9 is supposed to be banana oil! Whatever it is I like it a lot.
FWIW, I've tried several of the "non-toxic" cleaner/degreasers marketed and the "environmentally friendly" type of mineral spirits/paint thinner. It's wasted money IMO. One of the cleaners is called "Simple Green" and is supposed to be the cats. IME it's not even as effective as hot, soapy water, but it's a lot more expensive. Maybe I'm just impatient, but I'll stick with plain old diesel for parts washing, followed by an ATF scrub followed by an ether washdown if I want something really clean.