Left brown furniture items in store (6)
I believe the answer is:
lumber
'furniture items in store' is the definition.
(lumber can mean furniture items in storage)
'left brown' is the wordplay.
'left' becomes 'l' (common abbreviation).
'brown' becomes 'umber' (umber is a kind of brown).
'l'+'umber'='LUMBER'
(Other definitions for lumber that I've seen before include "Stored furniture; (US) timber" , "Move in ungainly way" , "Unwanted furniture" , "Jumble" , "Sawn wood ready for use" .)