Copper stain on brass

[Sully]

Bit of advice needed before I waste my time, can the copper colouring be polished off/out of brass fuzes and cartridges?

 

[HAZORD]

I believe the copper comes from using acid to clean the brass, which removes some of the zinc. Theoretically, polishing through the copper would get you down to a brass colored mixture again. I would suggest trying it on a spare piece of brass first before working on valuable things.

 

[smle2009]

Nope,brass is an alloy of copper and zinc,the coppering marks on brass is the result of electrolysis leaching the zinc content out of the brass,leaving copper.
Most commonly found on brass that has been in the ground for some period of time.

 

[Tmine35]

I have sometimes tried to polish the copper stains. They are often very deep and base material should be removed too much.

 

[Sully]

Thanks for saving me the time.