It was years ago, picked up a few bottles of the stuff at local WallyWorld during their post hunting season sale, think it was $0.50 or so a bottle. Remember thinking the bottles could be useful. My procedure when shooting my cap and ball revolvers has and still is to spray my moose milk (distilled water, Ballistols and Murphys) down the barrel, into the cylinders, the exterior of the gun, before rapping up on a cloth for the ride home. For some reason in a moment of mental weakness, I put a spray nozzle on a bottle of TC#13 and used it instead of my moose milk on a number of handguns after a day at the range. Same procedure as always, except for the TC#13. When I got home, maybe an hour or so later, I removed the cloths/rags, and to my horror, every handgun was covered with surface rust, externally, in the bores and cylinder chambers, and even the rags had rust stains. Luckily, I was able to clean up the mess with minimal damage to the bluing on the guns. Maybe it was the high temperature and high humidity, I do not know. Honesty, I would use urine for cleaning before I used TC#13 on my guns again, but that is just one person’s experience. At least you know what to expect with urine and how to address it.
@Africa58double, you asked.