A separator unit 21 is a cleaning auxiliary tool to be inserted into an air/water feeding cylinder 14. The separator unit 21 includes a partition plate 27 for partitioning an air feeding conduit 11 side and a water feeding conduit 12 side, and two elastic members 32b and 32d in an air/water feeding cylinder 14. The two elastic members 32b and 32d are arranged at an outer circumferential side of the partition plate 27. When an internal pressure on the air feeding conduit 12 side corresponds to an internal pressure on the water feeding conduit 11 side, the elastic members are spaced apart from an inner wall of the air/water feeding cylinder 14 by a predetermined distance, and when one of the internal pressures on the air feeding conduit 11 and the water feeding conduit 12 becomes higher than the other, one of the elastic members is deformed by receiving the higher internal pressure and comes in close contact with the inner wall of the air/water feeding cylinder 14.
