Can thwart them with something made from aluminium (7)

I believe the answer is:

tinfoil

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'them with something made from aluminium' is the definition.
I can't judge whether this definition defines the answer.

'can thwart' is the wordplay.
'can' becomes 'tin' (both are metal containers).
'thwart' becomes 'foil' (synonyms).
'tin'+'foil'='TINFOIL'

Can you help me to learn more?

(Other definitions for tinfoil that I've seen before include "Thin metal sheet for wrapping food etc" , "Rolled metal" , "Shiny food wrapping" , "Food wrapper" , "Metallic sheeting used for cooking" .)

I've seen this clue in The Irish Times.

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