Ed’s Red = equal parts each of ATF, kerosene, paint thinner and acetone.
Conveniently, those can all be gotten in quart quantities, to make 1 gallon.
I have used it to clean numerous guns with both polymer and wood furniture (including Glocks) ... never had any trouble with the acetone eating the plastic.
Acetone will eat or soften many plastics.
The solvent that I use that seems to be less aggressive on plastics is lighter fluid - the stuff that people used to use in Zippo lighters.
I’d be especially careful with acetone around some of the high-gloss finishes used on some guns - eg, the high-gloss finish on Browning rifles and shotguns is softened by acetone.