To start with, some cleaners regularly use brush! (5)
I believe the answer is:
scrub
'brush' is the definition.
(scrub brush is a kind of brush)
'to start with some cleaners regularly use' is the wordplay.
'to start with' says to take the initial letters.
'regularly use' becomes 'rub' (I can't explain this - if you can you should give a lot more credence to this answer).
The initial letters of 'some cleaners' is 'sc'.
'sc'+'rub'='SCRUB'
Can you help me to learn more?
(Other definitions for scrub that I've seen before include "Axe" , "Rub hard to clean" , "Curbs (anag.)" , "Brush, in two senses" , "Abandon" .)