For plastic solvent you can use mineral spirits, WD40, Liquid Wrench, Kroil, diesel fuel, Mobil 1S 0W-20, Brake-cleaner, Carb-cleaner, anyone's CLP, or any of about a dozen "firearm-marketed" solvents. They all work in conjunction with the cordless drill and brush. And I have never been able to tell that there is a whit of difference between them. Hence I use WD-40 mostly now. I would have added gasoline to the list, except I haven't personally done it.
There is one trick: time. Many use the solvent and immediately whale away. No. Spray/squirt/dump solvent and walk away. Come back in about six hours........or next AM. Then brush.
Sam
