For removing enamel paint, I found that nail varnish remover works well. Pour some into a container, dunk the model in it and scrub with an old toothbrush. Paint sometimes catches in the recesses but it is quite effective overall.
And before the funny replies pour in, I might add that it was my mother's bottle and not mine!
"At Victoria Station the RTO gave me a travel warrant, a white feather and a picture of Hitler marked "This is your enemy". I searched every compartment but he wasn't on the train".
Spike Milligan, "Adolf Hitler - My part in his downfall"