The other option is to remove everything by stripping the paint completely. In the UK, there is a product called Mr. Muscle Oven Cleaner. Although not designed for models, it will completely strip off paint, varnish, decals - the lot - without damaging the plastic. Apply it to the model, seal the model in a plastic bag and let the chemicals do their work. After a few hours, take the model out - wear gloves - and wash it under running water. The whole lot should rinse away leaving an undamaged plastic model.
I would suggest trying it out on something old first, but I have heard it works extremely well.
Hope this helps.