Does the Black Citadel Rust?

     Oh what an interesting question. You have this amazing, massive structure made out of ,what... iron, mithril, black steel, orichalcum? Maybe it's an iron-ghost dust alloy, that ghost stuff is everywhere and in pretty endless supply. Either way it's made of metal and lots of it and if it rusts somecharr has got to maintain it. I imagine the number of warbands needed to work on it is at least a centurions worth of them, maybe two. Maybe it's considered a pretty honorable job. Maintaining the citadel where the leaders of the Charr Legions meet and organize Charr victories.

“Centurion, I request duty on the Oxidation Removal & Eradication team.”
“What are your qualifications?”
“I've developed a black steel oxide inversion gun. It fires a measured, semi-coagulated spray of ignitor fuel, Old Claw's ginger marinate and Quaggan spit”
“You got Quaggan spit and ginger marinade to mix into a stable mixture?  That alone is note worthy." "Report in tomorrow and we'll see what you can do.”
“Yes Sir!”

Then again, maybe it's made up of disgraced gladiums or better said janitoriums.

Tribune Uberfierce - “For your cowardice I sentence you, Danus Lameclaw to rust and polish patrol!”

Danus - “No, anything but that!”

Tribune Uberfierce - “Report to Prefecture Miyagi Bottlebreaker immediately.”

You'd have to feel for those Charr thrown to the rank of janitorium, always being in proximity to some of the greatest Charr warriors and leaders but nevermore one of them. 

     I am more inclined toward the first example.  I mean, this is the Black Citadel, the symbolic representation of Charr power since 1112 AE.  Its the Death Star of Tyria for crying out loud!  You want the best Charr in there.  You want every visitor from the different races in awe of both the structure and it's personnel.  (Is it appropriate to say "personnel" when referring to charr?  Charrnel?  No, sounds like a bad cologne.)  Yes, it would have to be the best of the charr who make it to the Black Citadel and of those only a select few are allowed to maintain it.  What would the their name of their unit be?  How about the Iron Legion's Oxidation Removal & Eradication team or, the Iron ORE brigade?  Sounds catchy.