Boron must be swathed in cloth after girl handled container (7,3)
I believe the answer is:
carrier bag
'container' is the definition.
(carrier bag is a kind of container)
'boron must be swathed in cloth after girl handled' is the wordplay.
I cannot quite understand how this works, but
'boron' could be 'b' (synonyms) and 'b' is found within the answer.
'cloth' could be 'rag' (rag is a kind of cloth) and 'rag' is located in the remaining letters.
'girl' could be 'carrie' and 'carrie' is present in the answer.
This accounts for all the letters.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for carrier bag that I've seen before include "this from supermarket?" , "Hand luggage" , "shopper" , "Shopping container" , "It may hold purchases" .)