I have 3 horns, 2 trumpets both with lever style water keys, and a flugelhorn with amado water keys. The lever style keys work flawlessly, while the flugel (amado key) is almost impossible to completely drain the water from. Even with blowing and violent shaking of the horn, the fluid still is VERY difficult to drain, and this is a new Jupiter 846RS. Is it something I'm doing wrong? Is it hard to change to a lever style water valve? Any suggestions?