Naphtha or denatured alcohol, not Goo Gone.
Do not immerse or soak for any period of time, and most definitely not Goo Gone.
Use Naphtha or denatured alcohol to bring up the edges when peeling the paper off with a clean rag with your fingers.
Use the rag to blot the plastic.
Clean residue with a light circular motion, no scrubbing.
Keep rag and container away from open fire including all potential fumes, or you will understand the meaning of "flame on".
Many people do not realize how spontaneously this stuff can ignite, and it will suck the moisture right out of your skin leaving nasty second degree burns.

Goo Gone will leave unwanted residue and if not careful can discolor the plastic ink screening resulting in color blending and "bubbling".
Goof Off will melt and warp the entire plastic dependent on material, smear the ink screening at best, and "window pane" the plastic at worst.
Neither are good things for brand new plastics.

That is why you blot with a rag into the paper, not scrub or immerse. The paper absorbs the alcohol. If this method is followed, there is no paint removal, but does loosen the glue on the paper so your fingers can do the rest. Only dampen in order to maintain paper integrity. I never stated to use the alcohol with residue, you can use another diluted solutions of simple green or soap and water. If you careful, there is very little residue left to clean up anyway.

I have only had to use this method in some older NOS plastic sets. New repos still pull off fairly easily. This method should be used when you are having problems when the ink screening is coming off with the paper.