Brass Wire turnung Grey

I am puzzled about this, and maybe you guys can help. I made a small
crocheted purse out of 26 gauge brass wire, and trimmed with 26
gauge fine silver wire, After being stored for a while, the silver
looked dingy and the brass wire looked grayish. I tried polishing it,
with brass polish, several kinds of silver polish (not all at once)
and finally put it in my tumbler with stainless steel shot. The
silver polished up nicely, but with each treatment the brass seemed
to get more dull and ended up being a kind of gunmetal gray. I can’t
seem to get the brass color back. I thought that brass couldn’t
really lose it’s color. Can anyone tell me what happened, and is
there any way of saving it?

elegant Insects jewelry