How to liberate a collection without charge (3,4)
I believe the answer is:
set free
'how to liberate a' is the definition.
I can't judge whether this defines the answer.
'collection without charge' is the wordplay.
'collection' becomes 'set' (set is a kind of collection).
'without charge' becomes 'free' (sold at no cost).
'set'+'free'='SET FREE'
Can you help me to learn more?
(Other definitions for set free that I've seen before include "Clear" , "no longer detained" , "Uncaged birds have been" , "no longer confined" , "Release, remove restraints" .)