Blackener for side rods, valve gear, and drivers

[twilight]

I’m no longer satisfied with doing touch up jobs on side rods, valve gear and drivers with paint, I remember there was a product called Blacken It, but it doesn’t seem to made anymore. Was wondering what product you guys have found to replace Blacken It? I found a product online called Jax which has blackeners, has anyone used these? If so, which one? I’ll be using the stuff on Bowser, Mantua or John English running gear. Which I believe is brass at the core and is tin plated? I don’t think I’m interested in using Neolube because I fear it won’t play nice with DCC.

Thx,
Mark