Secure cash in Boston to conserve church decoration (4,6)

'boston to conserve church decoration' is the definition.
I don't know anything about this answer so I cannot tell whether it can be defined by this definition.

'secure cash' is the wordplay.
I cannot quite understand how this works, but
'secure' could be 'win' (I've seen this in other clues) and 'win' is located in the answer.
'cash' could be 'c' and 'c' is located in the answer.
This may be the basis of the clue (or it may be nonsense).

'in' is the link.

Can you help me to learn more?