Its already been mentioned above, but brake fluid works great, and I've never had any trouble using it, (I model armor however).
Get some sort of disposable container like an old pie plate or plastic ice cream pale, put your model in it, and cover it with clean brake fluid. Let the model sit for about 1/2 an hour and take a soft toothbrush, (make sure you throw the brush away when you're done), and slowly brush the model. If the paint doesn't start to come off, let the model soak a little longer.
Once you have completed removing the paint from your model, properly dispose of the fluid, toothbrush, and container. Wash your model thoroughly, and let dry. You are now ready to repaint. Good luck!