First I was following this guide http://oozinggoo.ning.com/forum/topics/how-to-fix-bubbly-lava-lava
It was a success at first try. I was also little too impatient, so I did not let the globe cooled down completely, etc for example. I have this little theory popped up in my mind at some point as I've looked at coil. The coil wasn't reaching all the edge of the bottom globe. There was talk of bad coil, the wax wouldn't stick to it, etc. I'd be going to think of it like a suction cup, as you can see, the "bubbly" wax was coming from liquid from the bottom, in the same way as the air enters the suction cup the moment it puts up to the glass wall. The suction cup would fall down quickly. The suction cup not sticking to the wall and the coil forming bubbly wax both give us the same unsatisfactory feeling. To make suction cup functional, there must be some way to prevent air from entering. Likewise, there must be some way to prevent the liquid from entering to the bottom--
It has to be all up to coil.
So, I've tried the guide in that url - I've let the lava lamp cooled down (well, due to my impatience, I've only waited until all wax become solid), I've carefully remove the cap (this will void warranty), then poured liquid out into a separate container, and at the meantime fill water into saucepan, put miniature plate inside, then fired up the stove top to medium-high, bring water to full boil, yes, actually full boiled. It's scary to think how the boiling water would boil the wax too. I've inserted globe in there for full 10 minutes and never mind the boiling water. After 10 minutes I took the globe out, I picked up the coil from globe (with chain of paper clips) and stretch it a little bit, trying to stretch to reach every edge down there. Apparently it doesn't matter if the coil become more crooked (at least not in my small globe). I've also swirled the globe a little bit, to let air 'n' liquid escape from coil, then let wax cooled down. The wax still has tiny bubbles inside but I think it's enough. I've poured liquid back in and sealed up the cap with hose clamp + flat head screwdriver, then immediately (due to my impatience) took to globe base and see wax in action... No more bad bubble problem! It's all groovy.
I can take picture of the result soon. I haven't had chance to take pictures of the process and how lava lamp looked before... sorry, only pictures of final result. My lava lamp is 11.5" White/Blue model number 1953.