They can be fired for putting money into safe places (6)
I believe the answer is:
blanks
'they can be fired for' is the definition.
The definition suggests an adverb but the answer is not.
'money into safe places' is the wordplay.
'money' becomes 'l' (L can mean 'pounds').
'into' means one lot of letters goes inside another.
'safe places' becomes 'banks' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'l' going within 'banks' is 'BLANKS'.
'putting' is the link.
Can you help me to learn more?
(Other definitions for blanks that I've seen before include "Cartridges with explosive charge but no bullet" , "Explosive cartridges with no bullets" , "Vacancies" .)