Lend a certain sparkle (6)
I believe the answer is:
aerate
This might be a double definition.
'lend' is the first definition.
Although both the answer and definition are verbs in their base form, I don't see how one could define the other.
'a certain sparkle' is the second definition.
The definition and answer can be both related to change as well as being verbs in their base form.
Maybe you can see an association between them that I can't see?
Can you help me to learn more?
(Other definitions for aerate that I've seen before include "Oxygenate" , "Put air into" , "Pass gas through" , "Introduce gas to" , "Let in oxygen" .)