Stump remover is the same thing for nitre bluing. Buying from Brownell's you have to buy a certain amount and pay for the shipping.
Walmart, Lowe's carries the stump remover. You just need a thermometer that goes to 1000 deg, and a heat source to get it there. The salts will liquify and become clear. My problem was that I could not get the temperature hot enough.


David