I can recommend the Kidney Cleansing Tea formula from Andreas Moritz 's The Amazing Liver Cleanse Book. You can buy one recipe of it from PresentMoment.com (1 recipe is a 20 day supply)for ~US$25.
Present Moment will send you all the herbs in one bag with a note to follow the directions in the book (see below;I'm assuming they need to do this for liability issues). I wasn't happy with the taste the first day I tried it, but after a few days I really looked forward to it. My body REALLY wanted the tea. I could feel things moving from my kidneys down my back to my sacral area. I assume that these were crystals or softened kidney stones. It was not painful. The feeling was like a very mild ached like when you stretch your muscles a little bit. Occasionally my kidneys felt like they were sqeezing themselves. Again, not painful, just interesting to notice.
If you order this from present moment,I suggest that you pour the contents of the bag into a big bowl, mix it thoroughly, then pour it bag into the bag.
To make the tea, put three heaping tablespoons of the herb mixture into a saucepan with one pint of water. Let it soak overnight, then simmer for 10-15 minutes in the morning. Strain it out. This will make about 1 1/2 cups of tea. It does not have to be taken hot or warm but you should not refrigerate it and should not add any milk or sweeteners.
You are supposed to sip this tea in 6-8 portions throughout the day and should wait at least one hour after eating before taking the next portion. Drink plenty of water while you are drinking this tea and plan to be near a bathroom as you will be urinating more frequently that usual. I pour the tea into a thermos and keep it on my desk at work so I can remember to drink it during the day.