Decades ago, I used nitric acid as a browning agent. I don't remember what I stored it in or if I cut it with water, but I dissolved a bunch of nails in it.
Hard to get it to stop rusting, and my fingers throbbed for a year or so. I also developed a condition of "thick-skin syndrome" or something like that. It
of course was my body reaction to the acid. I had to sand my trigger finger often, just to feel the trigger - the belt sander did a good job of that. Over it now, hands
as soft as a baby's tush (well, softer than they were for years)
That's back when I was young and impervious to danger.
Yes, be careful out there.