Neat experiment. You should try it again with artist grade pencils such as Prismacolor. I'm certain that warming the pencil softened the wax. Perhaps there is a better way to do that. Soaking has to damage the wood casing.

Alcohol also breaks down wax and is almost a trope among pencil artists. I like to apply it over the top of layers of color. You can also apply it to the surface before drawing. It is worth the experiment.