In Past, when stripping paint of old plastic model kits or resin models, I have found that one of the easiest ways to do this is to take the part, parts, or the entire figure and place in a ziploc plastic freezer bag. This done, get a spray bottle of easy off oven cleaner and, in a open, well ventilated area, spray into the baggy onto the model untill all surfaces are well coated, then seal the baggy after you  remove most of the air buy gently squeezing the sides of the bag.(It's not needed for the easy off to work) Let sit for a day or two, then (wearing safety goggles) use a old  tooth brush  to loosen old paint off the model.The thicker the paint, the longer you let soak and more often you brush with tooth brush, putting back in bag again afterwards, with another shot of easy off. I have used this method on old Aurora's Superboy kit, The Penguin kit, The Flying Sub. and others as well as on seven different resin kits. It did not harm the plastic or resin no matter how long they soaked in it, and washes off in warm soapy water.  And, unlike sanding, they did not lose any fine detail nor did it stain. If you are worried your kit is the one that turns out to be the one exception to the rule, take a small peace and try it first. Of coarse, you don't use this on rubber, Chrome or clear pieces; windows, tail lites etc. I hope this helps you out. Bob M