Harness Shopping - Bio with BRASS?!

I was just looking at russet and brass synthetics online yesterday. It’s on my wish list for Christmas!will check into the coating for sure.
After spending most of the day yesterday giving my leather and brass a good scrubbing.
Btw,best recommendations for brass cleaners? I need to get in all those little spots next time and will try the qTip trick. I’m still trying to remove the tarnish on my harness from when I bought it.
I’m going to just replace what little brass I have on my cart with new brass but the bras/russet look awesome with my red dun pony and the bulk of the cart metal is brown.