A method for cleaning a blood filter includes: (i) pumping a physiologically safe fluid back and fourth through the insides and/or the outsides of a plurality of hollow fiber membranes of the blood filter to remove or loosen blood residuals, such as blood clots, proteins and/or biological fluid； (ii) injecting air into the physiologically safe fluid to form an air/fluid mixture； (iii) pumping the air fluid mixture through the insides and/or outsides of the plurality of the hollow fiber membranes of the blood filter to further or remove or loosen blood residuals therefrom； and (iv) removing the air/physiologically safe fluid mixture along with the removed or loosened blood residuals to drain.
