Finishes as Aussies stumps regularly taken out (4,2)
I believe the answer is:
uses up
'finishes' is the definition.
'aussies stumps regularly taken out' is the wordplay.
'regularly taken out' means one should take alternating letters (letters removed at regular intervals).
'aussies'+'stumps'='aussiesstumps'
The alternating letters of 'aussiesstumps' are 'USES UP'.
'as' is the link.
(Other definitions for uses up that I've seen before include "drains" , "'Depletes (4,2)'" , "Consumes" , "Exhausts" .)