Mariachi Pa waylaid recruits to wear them down (4,4)

I believe the answer is:

chip away

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'them down' is the definition.
I can't tell whether this defines the answer.

'mariachi pa waylaid recruits to wear' is the wordplay.
'to wear' indicates a hidden word (I've seen 'wearing' mean this (the answer is covered by or 'wearing' the clue)).
'CHIP AWAY' can be found hidden inside 'mariachi pa waylaid recruits'.

Can you help me to learn more?

I've seen this clue in The Irish Times.

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