Corruption showed the way: made cowboy's charges disappear (7)
I believe the answer is:
'cowboy's charges disappear' is the definition.
I can't judge whether this definition defines the answer.
'corruption showed the way' is the wordplay.
'corruption' becomes 'rust' (rust is a kind of decay or corruption).
'showed the way' becomes 'led' (lead can mean to show someone the way).
'made' acts as a link.
Can you help me to learn more?
(Other definitions for rustled that I've seen before include "whispered" , "Stole cattle or made whispery sound" , "took stock" , "Stole (cattle, sheep, etc)" , "Stole (cattle); made a gentle noise" .)