Cartridge treatment?

Hi Guys, I received this 7mm rem mag HS Imperial the other day. It has a strange golden almost glow to it. It looks as if it has been coated with something. Does anyone know What would have been used?

Thanks,

Jonathan

Many of the older ammonia based case cleaners give the same result as you have pictured. You may notice a slight etching to the materials, both brass and copper, that can be felt to the touch.

Most notably seen on “battle field pick-up or salvage” materials. And yes on loaded cartridges!!

FrankN it almost has a waxy feeling to it. But it does not scratch or rub off. Very smooth.