Another possibility is ammonia. It is one of the best penetrants on planet earth, but takes time. As a for instance it will get every last bit of grit and gunk out of the crevices of an old style power steering pump reservoir, with lips and folds. Works MUCH better then acetone for that application even. But I soaked the thing for 24 - 48 hours.
Not sure if it's good for plastics. Use with caution. It will remove paint. But not necessarily all. I haven't had 100% success, but still considerable.
There also cleaning vinegar. Works to some degree.
The AK stuff is likely safe for all plastics, as it's intended use is Warhammer minis and such. All plastic for the last 25 years likely, or longer.
