I just came across Jorisch's article about copper doors, and on his blog he asks if anyone else has done oxidized metals. Well, I have, and now I fee bad that I never thought to post my HowTo here, as Mordheim is the /perfect/ place for such decay!
It would be remis of me to not put my research at your disposal my fellow mordheimers!
Some examples of my style:
Anyway, here is the recipes I use, hope it helps someone:
Also, super nice doors, Jorisch