You may want to try this product. It is made by Scalecoat same company that makes Polly S paint. I have used it on oil based, and water based paints. Tamiya, Testors, Polly S, and Model Master. It cuts them all and does not craze the plastic of your model. I use a medium tooth brush and just work it over the model to strip the paint. I use it over a plastic pan so I can recycle it to use again after I filter it through cloth back into the bottle. Use rubber glove if you use it.

Most Hobby shops with a good train section will carry it, but here is a web site for you to see what it looks like.

http://www.modeltrainstuff.com/Scale.../smz-10568.htm