Put to one side (6)
'put to one side' is the definition.
(I've seen this before)
This is all the clue.
(Other definitions for shelve that I've seen before include "Put on one 1 down" , "Put off indefinitely" , "Provide space for books" , "Store" , "Defer (a plan or project)" .)
(Other definitions for set apart that I've seen before include "Keep separate (for a special purpose)" , "Separated" , "specially allocated" , "Isolate" , "Isolated" .)