I would use a quart of water with about 4 tbsp of apple cinder vinegar in it, and sip that throughout the day before the night of the flush. I never had to use Epsom Salts which can be so hard on one. A quart of apple juice, organic with no added sugar, did the same thing but I preferred the ACV as it has less calories.
I used orange juice with the olive oil instead of the lemon or grapefruit juice. The result? With bimonthly flushes in about 6 months I expelled about 2000 stones. Now when I try to find any, I only get very few, so I am giving up flushing & just watching my diet.