Transport valuable metal criminal stashed in vacant house (7)
I believe the answer is:
haulage
'transport' is the definition.
(I've seen this before)
'valuable metal criminal stashed in vacant house' is the wordplay.
'valuable metal' becomes 'Au' (Au is the chemical symbol for gold).
'criminal' becomes 'lag' (slang term for a prisoner).
'stashed in' indicates putting letters inside.
'vacant' means to remove the middle letters (a vacant or emptied out form of the word).
'house' with its centre removed is 'he'.
'au'+'lag'='aulag'
'aulag' inserted inside 'he' is 'HAULAGE'.
(Other definitions for haulage that I've seen before include "Road transport" , "Transportation of heavy goods" , "Transport business" , "Commercial transportation of goods" , "Commercial transport of goods" .)