Stick tin next to middle of shelf (4)
I believe the answer is:
cane
'stick' is the definition.
(cane is a kind of stick)
'tin next to middle of shelf' is the wordplay.
'tin' becomes 'can' ('can' can be a synonym of 'tin').
'next to' says to put letters next to each other.
'middle of' indicates the central letters.
The middle letter of 'shelf' is 'e'.
'can'+'e'='CANE'
(Other definitions for cane that I've seen before include "Hollow jointed stem of, say, bamboo (4)" , "A stick to lean on" , "Sugar plant" , "Slender support, for 32 across say" , "Flog" .)