Bluing ferrules* is tricky. It requires near surgical cleanliness and excellent timing. We have been bluing ferrules for the better part of 15 years and now offer this service For those unfamiliar with what "bluing" is, bluing is a chemical treatment of, in this case nickel silver ferrules, that turns them from a bright chrome like finish to a dark charcoal almost black finish.
We use a multi step process to ensure a clean ferrule is ready prior to the bluing process. This involves hand polishing the ferrules and then putting the ferrules through a degreasing process. We typically apply two treatments per ferrule to ensure a nice dark finish across the surface of the ferrule. Male slides are masked** from the bluing and then the blued surface receives an enamel coating to protect it.
*Price is per individual full set of ferrules.
**We mask the male slides just above where the ferrule seats into the female so that when assembled there is no polished nickel showing.