Besides water and lemon juice, the following may help:
Pomegranate Juice - can lower acidity levels.
Basil Juice - contains acetic acid which helps break down kidney stones.
Apple Cider Vinegar - contains acetic acid.
Celery Juice - thought to clear away toxins that contribute to kidney stones.
Kidney Bean Broth - can help to dissolve and flush out stones.
Dandelion Root Juice - helps with overall digestion.
Wheatgrass Juice - can increase urine flow to help pass stones.
Horsetail Juice - can increase urine flow to help flush out the kidneys.
For a more detailed description, go to:
(this is useful, especially if you take medication)