Kept for future use (6)
I believe the answer is:
'kept for future use' is the definition.
(I've seen this before)
This is the entire clue.
(Other definitions for stored that I've seen before include "Stashed away" , "Kept for future use, as in warehouse" , "Squirrelled away" , "Put away for future use" , "Saved up in Dorset" .)