I don’t use liver of sulfur but instead Jax Silver Blackener on gold-plated
sterling (it’s just what I happened to purchase first, not specifically
preference). I apply it directly into the recessed area of the casting with
the tiniest paint brush with half the bristles clipped off. I’ve
accidentally painted outside the desired area too many times with a bigger
brush, and sanded the plating right off when I tried to clean it up with
any extra fine brushes/bristle discs.
I’d love to hear if anyone else has had success applying it in a more
oxidized allover finish with the bright highs and dark lows, though.
Especially for long-term wear, I generally find that oxidation comes off
after any prolonged wear.