I was thinking that massaging urine through the skin should clean out the pores and unblock eliminations channels, thus making detoxification through the skin more effective. Its not like you're putting on something that seals the skin off and stops it from "exhaling".
I agree with you on the liver flush. I will be doing one before my fast and will be following the fast with another series. I have already done 8 and so far, so good.