One could make light of this box (6)
I believe the answer is:
tinder
'one could make light of this' is the definition.
The definition suggests a singular noun which matches the answer.
'box' is the wordplay.
I cannot quite understand how this works, but
'box' could be 'tin' (I've seen this in other clues) and 'tin' is present in the answer.
The remaining letters 'der' is a valid word which might be clued in a way I don't understand.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for tinder that I've seen before include "Dry material for starting fire" , "Substance used to kindle a fire" , "It's used to start a fire" , "Kindling" , "Dry material to light the fire" .)