Out of metal? (3,2)
I believe the answer is:
not in
'out' is the definition.
(I've seen this in another clue)
'metal?' is the wordplay.
I cannot really understand how this works, but
'metal?' could be 'in' (In is an example) and 'in' is present in the answer.
The remaining letters 'not' is a valid word which might be clued in a way I don't see.
This explanation may well be incorrect...
'of' acts as a link.
Can you help me to learn more?
(Other definitions for not in that I've seen before include "ie Out" , "Out or away, house empty" .)