For most uses, the silver cladding is etched away by acid to expose the platinum core.
The tin/lead becomes the resist leaving the bare copper to be etched away.
Electrical contacts are deposited and then selectively etched away.
But a black spot has to be etched or scraped away, a ticklish process requiring a surgeon's skills.
Gradually the fear had been etched away.
The exposed metal is etched away, leaving the pattern of connecting metal between components.
Parts of the wafer are then etched away, leaving a rigid silicon frame that holds the membrane in place.
The limestone was etched away using a mild acid.
However as a practical matter, the less gold that is present, the more other material must be etched away to produce the desired surface appearance.
The graphite is chemically etched away while the diamond slowly accumulates.