Isopropyl alcohol my friend. Available in most well stocked drug stores and pharmacies.
Find a plastic container just a bit bigger than the model's all around dimensions so that the model will go in comfortably but not leave too much extra space.
place the model in the container and pour in the alcohol straight from the bottle over top of the model until the bottom of the container is completely covered in alcohol.
Fill the container with hottest tap water (do not use boiling water from a kettle) to fill the container the rest of the way until the model is submerged completely or as much as possible and then put the cover on the container loosely. Do not push the lid down to seal it, you just want to keep things warmer longer and slow down the alcohol's evaporation rate a bit.
Place the container in an out of the way spot away from ignition sources and let it sit overnight.
The next day, take an old toothbrush and give the model a scrub with it. the paint should be softened enough that you can get some of it off.
I find this method works well with both enamel and acrylic paints. As your model is no doubt painted with enamels, you may have to repeat the process a few times before getting all the paint off.
The alcohol will not damage the plastic at all and if there are clear parts it wont craze them.
All around its just safer for your health and your model. It may not be the fastest stripping method mentioned here, but think of the extra time involved as extra piece of mind.
Good luck in your project.