Hand two little boys cleanse (5,5)
I believe the answer is:
royal flush
'hand' is the definition.
(I know that royal flush is a type of poker hand)
I don't understand the remainder of the clue.
(Other definitions for royal flush that I've seen before include "pulling of chain having vacated throne?" , "Sign of top family's embarrassment" , "Result of embarrassed Queen" , "evidence that monarch occupied throne?" , "Excellent hand" .)