I was recently reading Shadows for Silence when I had a conundrum.
They say that it is silver that is what is used to attack shades and protect the waystops.
While scrounging through Arcanum, i found this quote
We know that investiture can be messed up with aluminum, seeing as how aluminum is basically the null of the Cosmere, preventing invested objects or investiture in general from being used/ detected.
So here is the theory:
Silver on Threnody is actually just aluminum.
This is due to the fact that aluminum can screw with investiture and aluminum can protect against certain forms of investiture a la Lashings and Emotional/Steel/Iron Allomancy.
We also know that this wouldnt be the first time aluminum has been given a different name, seeing as how Ralkalest is actually just aluminum in The Emperors Soul.
What do you guys think? I'd love some feedback.