During various military combat survival courses I've undertaken in the past we were taught that urine is quite a good antiseptic, and that to use it in the aforementioned manner is quite a good practice in the absence of anything else. Some instructors reckoned it was a good idea even
in the presence of alternatives. Have used the practice quite a few times myself, out in the bush as well as after rough days diving around reefs, and have had only successful healing. That, of course, doesn't certify cause and effect.
The only real decision to made is, if it's in a hard to reach place, choose wisely who you get to piss on it for you

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