I was trying to think of all the sacrificial things. Sacrificial anodes
on ships, yes. But... how about the face of a wooden mallet? Because the
reason it's wood is because steel would be too hard. Because the wood is
softer it's more likely to get damaged. Stretching a point? A wooden
gramophone needle, which wears out quickly but doesn't damage the
shellac? Can anyone think of sacrificial things?

Bill