Yes you can paint shiny brass ,

I sanded the smooth parts, yes sand the brass, it will help the paint stick.  Spray it with a black flat metal spray paint. When dry, paint the whole thing with white chalk  paint. If you are looking to destress it, rub off some of the white with a damp cloth before it drys so some of the black shows through.  I wish I had a photo of it hung, let me know what you think.