I have done over 20 flushes and the last 4 have produced nothing. I think I still have a few stones because of some mild discomfort just under my ribs so I'm currently fasting on apple juice in preparation for the next one.
A while back, I did an experiment mixing olive oil, Epsom Salts , lye, grapefruit juice and water. The lye was an attempt to simulate stomach acids. I kept the whole thing near body temperature for several days. A hard, soap eventually formed, but it was water soluble. It also got harder when exposed to room temperature air. Some of my stones melted when exposed to air and none were water soluble. Conclusion is you don't have to heat olive oil to 300F to produce soap as has been suggested, but what comes out during the flush is NOT soap.