Clean house again (6)
I believe the answer is:
hoover
'clean' is the definition.
(hoovering is a kind of cleaning)
'house again' is the wordplay.
'house' becomes 'ho' (abbreviation for house).
'again' becomes 'over' (as in the phrases 'start over' and 'start again').
'ho'+'over'='HOOVER'
(Other definitions for hoover that I've seen before include "US president, 1929-33" , "Vacuum-cleaner" , "J Edgar . . . . . . was FBI chief" , "US president in House throughout" , "Type of 5 down" .)