Family members left in ceramic oven (4)
I believe the answer is:
'ceramic oven' is the definition.
(I've seen this in another clue)
'family members left in' is the wordplay.
'family members' becomes 'kin' (I've seen this before).
'left' becomes 'L' (common abbreviation).
'in' is an insertion indicator.
'kin' enclosing 'l' is 'KILN'.
(Other definitions for kiln that I've seen before include "Drying furnace", "Industrial furnace", "Hops or pottery cooker?", "Pottery furnace", "Large commercial oven".)