I'll preface this by saying my POV is from someone living in SoCal and dealing with the over-reach of SCAQMD into our daily lives.  In 2015, mineral spirits was effectively banned in most of the state. The replacements are nasty and much more toxic. The green replacements dont work well.  I posted this on Reddit today.

So lets start with what is mineral spirits. It's a refined petroleum product that has had the smell mostly removed and you will it described as:
n my RADAR till recently since I had a gallon circa 2000 or so and never really used it till recently when I picked up oil painting. Then I found out when I bought some Kleen Strip green mineral spirits and I got this nasty milky white crap. Most sellers wont sell it to me since I live in CA. Amazon is the same. I could drive 5 hours to Az to buy it or some sections in Northern Cal that the SCAQMD rules do not apply. I can also buy small amounts in the art stores at high prices. But, I know you can always find stuff like cheap if you chase the paper trail.

So lets start with what is mineral spirits. It's a refined petroleum product that has had the smell mostly removed and you will see it described as:

Petroleum distillates, hydrotreated light

And for a can of mineral spirits, you will see that description, the CAS number and the percent of the mix which in most cases is 100% or 100% pure mineral spirits. The SCAQMD replacements are NOT 100%.. they are a blend of mineral spirits maybe 10%and other noxious stuff like acetone upwards of 70% and other crap. And they warn it's more flammable, more smelly, more bad. And it doesnt work well as paint thinner regardless of what they say on the label

The key to this is the CAS number which is a unique identifier of American Chemical Society for a given ( single ) chemical and link to information on that chemical.

CAS-6472-47-8

This is the CAS number for odorless mineral spirits. Or Petroleum distillates, hydrotreated light

You find that number and you have mineral spirits. Now, SCAQMD has banned this in much of California. But, as it turns out I can buy it all day long, every day of the week in any supermarket, 7-11, or big box store. What you say? how can that be???

Kingsford Charcoal Lighter Fluid

Yep.. lighter fluid for your BBQ is really mineral spirits in disguise. 100% and the safety sheet says it..

CAS-6472-47-8

I bought some today.. cost me 3.50 for a quart and guess what? it works just as expected in thinning paint, cleaning brushes, cleaning hands and a hint of oiliness. I can buy a gallon or a tanker load in California by ordering LPA-170 Solvent.

https://ace.infotrac.net/getmsds.aspx?sku=8273492

All this information is public record if you take the time to dig it out.

By comparison, most art supply houses are selling a quart of odorless mineral spirits ( outside of CA) for 10 to 15 dollars. The crap in CA costs even more for an inferior product or a very small amount of mineral spirits. White spirits is going for 20 dollars a quart. Given that BBQ starter fluid is 4 dollars a quart or even less, you can save a fair bit of money.