WRT safety its probably a taste thing. Diluted enough, the nitric could easily be made weaker than your stomach acid but will still eventually dissolve the cop

WRT safety its probably a taste thing. Diluted enough, the nitric could easily be made weaker than your stomach acid but will still eventually dissolve the copper. Its a sort of linear-ish relationship of concentration vs time so you can trade safety for time (as with most industrial processes, LOL) I would think dilute iron chloride would not taste good, but you could probably chug enough to get sick. I believe there would be a similar relationship WRT staining skin and clothes, dilute enough HNO3 would not be TOO much more dangerous than letting kids handle a can of Mt Dew unsupervised, but FeCl in any dilution will stain and damage clothes and skin. If I had to work with maximal concentration solutions of both, I'd agree and definitely prefer the conc FeCl vs fuming nitric.