Cleaning oxidized metal railings and fittings

I have a couple of old run Rivarrosi steam engines that have green oxidized railings and small fittings. I have tried some vinegar, lacquer thinner, Noxon polish and nothing really does much. Does anyone have any suggestions short of replating them? I even tried scraping them with an Xacto blade and then using a metal blackening solution,which isn’t too bad but not like the originals were.

-Bob

Brass-o and Qtips. It’s an absolute pain, but it works.

Stu