oxidized? brass turns a golden brown when oxidized, the balls are usually steel though, so you have a rusty ball valve? Rust will impart a bad taste (minerally - irony - blood-like)
Doesn't brass start to turn green or is that just bronze? I don't remember because I use stainless steel. It only costs a few dollars more to do things right. I don't mean this as a "let them eat cake" statement. But if you can afford the right fittings, valves, QDs etc, it will save you time, worry and eventually money.
