Extracted from a paper titled “Practical Advice on Getting a Piercing” [I finally got a new one today 😉 ]:

Salt water is the leas reactive and most effective cleaning solution (1/4 teaspoon of salt to one cup of clean water). Also good are seawater and your own urine. Urine is a sterile cleaning agent as the uric acid it contains kills bacteria without hindering the formation of new cells.