Nitre Blue salts are readily available at most smith sources. The salts are boiled straight without the addition of any water in a steel tank to over 600 F, I use 625 F. Small steel tanks are available from Brownells for this purpose.

The cleaned and prepared parts, same cleaning as rust blue to 600 W/D, then they are acetoned, dried then dipped into the tank and shortly you have your nitre blue finish.....the lower you drop the temperature the lighter the color. I leave the parts in the tank usually about 10 minutes.

I hang the parts using a small roll of medical stainless steel wire that I have, surgical wire. Very small diameter and it will twist over almost any thread size or opening in the parts/screws etc.

Regards,

Doug