first of all find yourself a can of oven cleaner you can buy it any grocerie store and its not all that expensive. Once you have purchased it set up you model that you want to strip the paint off of in a well ventilated room since oven cleaner is extremely toxic. Apply the oven cleaner all over the model and make sure you are wearing rubber gloves of some sort to protect your hands. After about 15-20 mins the oven cleaner should have done its job of loosening the paints grip of your model it will not damage the plastic unless the cleaner has been left on for a substancial ammount of time. The next step would be to find an old toothbrush not one of your own for obviouse reasons and scrub the model for a while be carefull around sensative areas around flimsy details on your model. After a few mins of scrubbing the oven cleaner will start to go whatever your paint colour was. once you have scrubbed for a substancial amount of time rince the model in warm water and if needed dry it and use the toothbrush to scrub away any left ove paint.
