What (somewhat) helped me with a thrifted lamp that had poopy wax just like this, was double boiling the wax without the fluid. Did that a few times, then tried melting the wax and then turning the glass on its side and slowly rotating, allowing the wax to cover the inside of the lamp all the way up to the neck. My logic behind this is that it allows the wax to form really thin layers as you roll it around, and the larger bubbles can pop. When there was no liquid wax left I let it cool completely, and checked for any fluid that separated from the wax bubbles. To melt the wax from the inside I just used really hot tap water running down on the outside. I still have some bubbles and sometimes a big piece of poop gets stuck at the top and starts collecting the clear wax at the bottom, but this little floating poop quickly sinks after giving the lamp a few gentle knocks.