Because we're treating the surface of the Nickle-Silver parts, it's important that those surfaces be cleaned very thoroughly. You must wear gloves when you do this, as even the natural oils from your hands & skin will contaminate the surface & interfere with the bluing treatment. Only after all the parts are cleaned & prepared, can you begin.
The bluing agent is then applied by hand. You must work fairly quickly & try to get an even coating. The part is continually in motion, being turned, so that the bluing isn't darker in one spot than another.Once the rod part is colored sufficiently, the chemical reaction of the bluing agent is halted by rinsing the part in water.
As this is a surface treatment only, you can't blue parts of a rod that will have friction, like the threads of a screw-locking reel seat or the wire line guides, but you can blue the slide rings in a seat. Of course, cap & ring style reel seats are no problem. If you want the wire line guides & tip tops dark, it's best to buy the commercially coated black ones, or ones made from titanium. After many years of use along the stream, the bluing will fade & wear off a bit. That's why it's not uncommon to see vintage rods with blued metal parts that have faded a bit.