What to do with metal chain?

I agree with the gun bluing solution to darken steel or in this case white metal Friul tracks. I tried it for the first time last week on some Friuls. It darkened them up quite a bit and added a bit of rust/oxidation to them. AK makes a darkening solution as well. I think it has the same ingredients as gun bluing solution. I'm not sure if it will work on brass however.

Good point Stik.  I have a bottle of KleenBore Black Magic somewhere in the garage.   I’ll give it a shot on the brass, I’ll definitely try it on some Fruil tracks if I ever get a set. 

Brass is a bit of a different equation. But the guys at AMPS have mentioned using gun bluing liquid (for actual firearms) to do the same thing with Fruil metal tracks.