Metal detector? (6)
I believe the answer is:
copper
I believe this clue is a double definition.
'metal' is the first definition.
(I know that copper is a type of metal)
'detector?' is the second definition.
(I've seen this before)
(Other definitions for copper that I've seen before include "old tub" , "Metal, Cu" , "Busy" , "Little money" , "Reddish metal of a penny" .)