Target substrates are electrostatically coated by flowing an electrically isolated wet coating composition containing waterborne coalescable polymeric binder into an electrostatic coating apparatus (100), depositing the coating composition onto a rotating electrostatically-charged atomizer (104) and then onto the target substrate, flowing an electrically isolated aqueous cleaning liquid into the apparatus before deposition of the coating composition onto the rotating atomizer is halted or interrupted, and depositing the aqueous cleaning liquid onto the atomizer before or within a sufficiently short time after a halt or interruption in coating composition deposition onto the atomizer so that a coalesced polymeric binder film does not accumulate on the atomizer.