Potassium Chlorate is mixed in a soln,,you buy it as Mark Lee's Express Brown or Blue Soln.
It's been on the market for about 40 years and no one has ever had a bottle of it explode that I've heard of.

You can make your own potassium chlorate from common bleach and potassium chloride salt substitute.
Yes it's a strong oxidizer and needs to be separate from certain other chemicals. But so do alot of other common chemicals and compounds.

Iron Trichloride is more commonly known as Ferric Chloride.
Damascus etch is the common gun finishing use and it's also found in many rust bluing formulas.

This is Rust Brown Soln,,,,,Boiled and carded
[Linked Image from i.ibb.co]

[Linked Image from i.ibb.co]