Almost destroy new oven (4)
I believe the answer is:
kiln
'oven' is the definition.
(kiln is a kind of oven)
'almost destroy new' is the wordplay.
'almost' means to remove the last letter (most of the word but not all of it).
'destroy' becomes 'kill' (I've seen this before).
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'kill' with its final letter taken away is 'kil'.
'kil'+'n'='KILN'
(Other definitions for kiln that I've seen before include "Furnace for firing bricks" , "Potter's furnace" , "Oven for burning lime" , "Drying furnace" , "Large commercial oven" .)