From Quora:
Related: What’s the proper way to dispose of a lava lamp?
All Lava Lamps MUST be disposed of in active volcanoes, otherwise the Lava melts a hole in the ground and goes to the center of the Earth. And whatever you do, do NOT break a Lava Lamp, the Lava is carefully suspended in the Lava juice, and any exposure to air will allow it to start the process.
I was actually looking for advice on how to refill one, which I also found. But the above left me giggling all morning and I had to share.