neesay is right, MH doesnt even recommend a flush any more except in emergencies. taking a tablespoon of lecithin every night before bed is what he says will slowly clean them out. if i were you i would spring for the organic soy lecithin from clarckson and mix it 50/50 with organic cold pressed xtra V california olive oil. together, they should do the best job and the least harm. MH thinks the organic lecithin is not necessary and outrageous in price(it is), but i have had a sample of clarkson and it is worth it in my opinion.
chinese bitters is what i was thinking about. ask the folks on the liver flush about that.
maybe you can soften up the stone with apple juice and bitters and flush it out with tons of epsom. it is the epsom salt that relaxes the bile duct.