Boats made of sticks, with nothing inside (6)
I believe the answer is:
canoes
'boats' is the definition.
(canoe is a kind of boat)
'of sticks with nothing inside' is the wordplay.
I cannot really see how this works, but
'of' could be 'o' and 'o' is found in the answer.
'sticks' could be 'canes' (cane is a kind of stick) and 'canes' is present in the remaining letters.
No letters remain.
This explanation may well be incorrect...
'made' is the link.
Can you help me to learn more?
(Other definitions for canoes that I've seen before include "Simple boats" , "Craft" , "Small boats found in strange oceans" , "Small light boats" .)