While I haven't tried this on a PMag... nor the clear window on the PMag
It will remove paint overspray from vehicle plastics. And very easily.
WEAR your safety glasses... because any scrubbing could fling the product into your eyes.
An extra moment taken to put on safety glasses ... is time well spent.
If your hands are sensitive, or you have more then a few to do... wear rubber gloves !
Disassemble the mag placing the follower and spring away from the work area.
I suggest you do the work outside... so you don't splatter the product on the kitchen / bathroom walls paint or other surfaces.... it will remove paint.
Spray it on, allow it to sit for a 10sec... scrub with veggie brush ... Then THOROUGHLY rinse with water, while scrubbing again.
Again, try it on a sample one first, prior to going bat poop crazy.
http://www.tswwarehouse.com/tsw2r-multi-master.html