MortiS suggestion of Dettol is well worth noting.I have used an old bottle of Polystrippa paint stripper which even does polyurathane paints.However I do not use it must & they might not make it anymore............this bottle was £1.15 & is over 20 years old.It comepletely took GW gold off a GW black plastic case,with no residue.Another useful idea is to buy a plastic pickle container(if they still make them)from Tupperware 14cm high x 9.5cm diameter.......it contains a lift out 'floor' to raise your onions/figure out of the vinegar/Dettol.........so you can give them a good soak.I have never had much of a result with White Spirit or spirits of Turpentine,except with oil painted figures.I have used Acetone,with mixed results.Acrylic is quite stubborn,I will try the Dettol,its cheap enough!
The Prodigal son