The apple juice method I did was:
Every day for a week leading up to the flush, juice a litre of organic apples. Add a TBSPN of olive oil. Drink 4 x 250ml during the day. Then on the 7th day, do your grapefruit juice/olive oil (1 cup each) drink just before bed. (I didn't do Epsom Salts then, it was just as effective). The stones were not bright green and shiny, this is going back a few years so I can't describe them well but I do remember being surprised at how different they were to the first two times I had flushed. Like acid had started breaking them down - kind of paler and more porous.
I think there is an outline of a similar apple juice flush on the Liver Flush homepage.