Someone needs to pipe up for Mother. If you buy into the mineral spirits claim you might as well start bathing in mineral spirits. Heck, let's add it to our dishwasher. It could go in the rinse aide dispenser. Haha

Nobody would consider washing their clothes in mineral spirits (though they are used in dry cleaning) but there's a rush to the hardware store every time the subject comes up. Mineral spirits are toxic, they are highly volatile, their fumes can cause brain damage if you don't properly ventilate or wear breathing apparatus. I would be very circumspect about keeping them in the house/garage, unlocked, where young children play.

I don't know about Simple Green and I'm not interested in debating its merits but I can tell you this. You can safely use a citrus-based solvent that sees the start of its life in an orchard, not a oil field, and ends with safe disposal. Contact your local materials handling authorities for exact details.

You could say, "All I want to do is clean my drivetrain, quick and easy. The mineral spirits sound simple." I'd respond, "You could drive your car, but you ride a bike."