Cosmetics worn by Irish friend in service (8)

I believe the answer is:

mascaras

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'cosmetics' is the definition.
(mascara is a kind of cosmetic)

'worn by irish friend in service' is the wordplay.
'worn by' indicates putting letters inside.
'irish friend in' becomes 'cara' (I can't justify this - if you can you should give a lot more credence to this answer).
'service' becomes 'mass' (kind of church service).
'cara' inserted inside 'mass' is 'MASCARAS'.

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I've seen this clue in The Irish Times.

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