These might be smuggled in 500 carpets (5)

I believe the answer is:

drugs

'these might be smuggled' is the definition.

'500 carpets' is the wordplay.
'500' becomes 'd' ('d' can be a synonym of '500').
'carpets' becomes 'rugs' ('rug' can be a synonym of 'carpet').
'd'+'rugs'='DRUGS'

'in' is the link.

(Other definitions for drugs that I've seen before include "Medication" , "Narcotics" .)

I've seen this clue in The Guardian.

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