I happened to have one light that still lit, but had no liquid left inside, and one like that had liquid with a burnt out bulb. I decided to see if I could make one working light out of the 2 broken bulbs.
This is how the bulbs are supposed to look:
Step 1: Burnt Out Bubblers
One bulb had lost its liquid somehow, probably through a flaw in the glass or maybe I didn't pack them away carefully enough.
Another bulb burnt out, and could probably be replaced, but the base of the bulb is fused into the plastic housing and I don't want to put it back together if its going to wiggle or wobble at all.
Step 2: Swapping Parts
Just like the bulb in the base, the bubble vial is securely fused/glued into it's plastic holder. Even though I would like to stick with the standard color scheme (green-yellow-red or yellow-red-blue) it would be a shame if I broke something now because of something so silly. Instead, I figured I should just swap the tops and bottoms of these 2 bulbs and make one working bulb and one completely broken one.
I ran a thin blade along the seam between the 2 colors of plastic. Once the knife gets into the seam, it starts to separate and makes a nice popping noise. If all goes well, the seam will pop open without cracking either piece.
Before you try to glue anything, dry fit the halves of the bulb. There are two protruding keys on the top that fit into depressions on the base. Once you get the top and bottom to fit with a tight seam you are ready to glue it.
I used Krazy Glue, but you could probably use any super glue or model glue.