It's a tough situation, anything that "polishes" will be abrasive, and that brass nightmare is chemically blackened. It'll come off just as easy as the corrosion...
I'll dig around in my parts bin, see if I have any brass parts with comparable corrosion to test some things on. I'm wondering if something simple as a soak in vinegar would work (without removing black), or if Evapo-rust would touch it (formulated for iron oxide, but worth dunking a test piece...)
My feedback: MCB
Originally Posted by The Flounder
We don't do easy here! Here we do different and not done before!