Large metal pot used by peculiar dour clan (8)
I believe the answer is:
cauldron
'large metal pot' is the definition.
(I've seen this before)
'peculiar dour clan' is the wordplay.
'peculiar' indicates an anagram (a peculiar or strange ordering of the letters).
'dour'+'clan'='dourclan'
'dourclan' with letters rearranged gives 'CAULDRON'.
'used by' is the link.
(Other definitions for cauldron that I've seen before include "Very large metal pot for boiling" , "Witches' vessel" , "Witch's brewing pot" , "Large cooking pot" , "Place that's seething" .)