Hey, you could use it in a in-cowl airplane since it's dark, it won't show.

Just kidding. I haven't heard about the antifreeze method... I was told if you left the body in carb cleaner too long it will turn black and that I'd be stuck with it. Next time have a timer set up so you won't leave it in the solution for too long. That's what I do. Maybe you should re-post this in the engine forum, I'm sure one of those guys can help you.
Pete