As I mentioned earlier, the LavaLamp I have is a smaller cylindrical one. It uses a small intermediate base 15W bulb as a heat source. Forty years ago it worked just fine until it got shaken up. Since then, the best it's done is sending up little pale jagged strings which don't remelt.
Anyway, I tried andy's suggestion. Poured out the liquid and held the bottle in boiling water so that it didn't touch the bottom of the pan. Wow! Hey, great, the wax is all back together again in an even disc at the bottom. Let it cool for a couple of hours and then poured the liquid back in and plugged the lamp in... this is gonna be great! Six hours later... nothing. No runs, no drips, no globules... nada!
The little 15W bulb is all silver and black, it looks like it's blown but it does work. I've looked all over and can't find a replacement. However (Eureka!), I do have this 40W high intensity bulb with an intermediate base. The wax is warm from the 15W bulb so the 40 shouldn't take long, right? I can turn the lamp on and off to regulate the heat, right? Put in the 40W and turn it on, keeping my hand on the base to check heat, gets too warm, turn off lamp, etc.. Well, a few minutes later a single string spews from from the center of the wax disc and then the rest of the wax expands like a sponge and sticks to the side of the bottle like a big pink loofah!
Doh!
I think this lamp is going to continue it's journey to the curb.
BTW, I, in no way, fault andy's advice. I clearly exceeded the design specs.