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.
Wonderful! Thank you so much for the tip, @neopatriarch! 😊 I definitely would love to try that next time. I'm pretty new to colored pencils, so I'm eager to learn a lot about them. Thank you for dropping by. 😁
P.S. I'm planning to buy Prismacolor (or maybe Polychromos) in the future. And yes, maybe try this experiment again + the one you suggested. 😃