mineral spirits, kerosene, and paint thinner are NOT FLAMMABLE. They are combustibles. You can drop a lit match into a bucket of kero and it will put the match out. But soak a rag in it and put a lit match to it and you will get a nice fire. Now lacquer thinner, gasoline etc is flammable meaning they don't need a carrier(wood,cloth,paper) to ignite. The vapor that these liquids puts off is what burns which is what makes them more dangerous. I would not use mineral spirits as a cleaning solvent in a parts washer. It is not to healthy to breath and you must be careful to properly store your dry off rags. The new citrus cleaners are biodegradable, work well,and are safer.
*bonus*...When you are done you smell like an orchard nor a refinery