Bundle up citrus soap boxes (5)
I believe the answer is:
truss
'bundle up' is the definition.
(I've seen this before)
'citrus soap boxes' is the wordplay.
'boxes' indicates the answer is hidden within the clue (to box can mean to contain).
'TRUSS' can be found hidden inside 'citrus soap'.
(Other definitions for truss that I've seen before include "US state" , "Corbel, in architecture" , "Roofing frame" , "Surgical support" , "Architectural corbel" .)