It all depends on what kind of paint. Enamels will strip better then acrylics.
For all my restoration I use oven cleaner from a dollar store. You might have to soak the model a few times.
Some have said to use Brake Fluid. This will take the paint off but will take days and days. I think it only works a few hours then it's a waste. Also its hard to get ride of the stuff after you are finished. With oven cleaner you can just rinse down the sink.
my website shows the Phantom model before and after taking all the paint off.
GOOD LUCK!!!
Dales Model Art
http://community.webshots.com/user/dales_model_art