Taps are steel and are easily dissolved in muriatic acid.
Bronze will lose a little tin at the surface (or zinc if it's really
brass), but will not be etched away by muriatic.
Wear gloves and goggles. Carefully add muriatic acid to the hole.
Bubbles of hydrogen gas will form as the tap dissolves. You needn't
dissolve it completely - just enough to allow you to screw it back out
using needlenose or some such tool.
Bruce
NJ