The print head cleaning system carriage can be completely removed. Need to push the carriage to back of printer. Remove screw in back right corner, next to the black cylindrical pump with rubber hoses, and another in the gear assembly that runs this pump. Then wiggle and remove this pump/gear assembly. Now the carriage can be moved forward on the track till a slot allows getting past a small metal shaft and a gear. Now you can clean it in the sink with hot water. Be careful to put the two springs back on this carriage before putting it back into the printer.
And be sure all the tubing will freely flow water, or the pumping action will not work!