Most toxins are extracted by the liver

"Maybe the body takes toxins out via urine that is ideally very dilute. So a small amount as you say could be effective a la homeopathy."

Toxins are extracted by the liver which empties into the gallbladder which empties into the colon.  Tests have found that raw garlic combines with the heavy metals in the liver, and exits that direction.  Urine doesn't have the toxins in it that fecal matter does.