Very interesting and I have been using Mineral Spirits as my primary cleaner, for years. That includes the cleaning of M/L's. Have never seen and gun company recommending it and good info. The last gallon I bought, cost me around $5.00. I also reuse it and when it finally get too dirty, I use it as a fire starter it is not very volatile. You should observe proper ventilation. ....
Mineral spirits is the base to dry cleaning fluids. It is like a dry kerosene. It is also paint thinner.
When I was a Class 3 , I was also in the oil and gas business. I set up a parts washer with mineral spirits to clean the guns after shooting WW2 ammo. I would leave the gun broken down in the m/s with the pump that runs on air to flush out the dirt for 2 or 3 hours. The bad side was that you had to be ready to oil or grease the gun when removed from the parts washer.
For a time I had a 20,000 gallon above ground tank for the mineral spirits that had a 24" manhole. I would take webgear and tie it on a rope and put into the tank for 24 hours to remove dirt and oil. Most of the time the gear would come out looking like new on duck or leather.
The best part about mineral spirits is that it allows the dirt and trash to "drop" to the bottom when it is allowed to rest. Then you can pour off the clean and dispose of the trash on the bottom. Used it many times to clean M-1 stocks so I would not have to refinish them.
Yep, it'll work, but it's not the most effective way to get at carbon, copper or lead fouling. For those jobs, (and equally cheap), I use Ed's Red...a home made concoction originally put up by Ed Harris of American Rifleman's "Dope Bag" fame. Do a search for all the details, but it consists of equal parts by volume of: Ed's Red = Kerosene, Acetone, Paint Thinner, and ATF Transmission Fluid .
I started using a mix in eqaul parts of Kano, Mineral Spirits, Hoppe's#9 and Marvel Mystery Oil. Has been doing a good job with lead removal, which is all I shoot.