Well able to afford a wash (5)
I believe the answer is:
flush
'a wash' is the definition.
(I know that flush is a more specific form of the action rinse)
I don't understand the remainder of the clue.
Can you help me to learn more?
(Other definitions for flush that I've seen before include "Poker hand of same suit" , "Level (with surface); put up (game bird)" , "Go red" , "Rouse game and put to flight" , "Cleanse by running water" .)