Apparatus (10) for cleaning fluids such as oils comprising an inlet (12) for fluid to be cleaned, a heating unit (21) for heating the fluid, a centrifugal cleaner (24), a vacuum dehydration unit (26), a holding tank (11) and a fluid outlet (40). A first valve (13) controls communication between a first pump (20) and the inlet (12) or holding tank (11) to pump fluid from the inlet (12) or holding tank (11) to the heating unit (21) for conveyance to the centrifugal cleaner (24), the outlet of which is connected to the vacuum dehydration unit (26) and a second valve (37) controls communication between a second pump (35) and tank (11) and outlet (40) to either enable fluid to be recirculated back to the tank (11) or supplied to the outlet (40).