Just recently, when I wash the windscreen with the washer-jets I get a really horrid smell. Smells like someone urinated in my washer bottle. I normally use a nice-smelling screen wash from my local car store. Is there any way to empty the screen-wash tank without just spraying it out? also, what could cause the smell ? I don't believe that screen-wash goes bad. Could there be stale water at the bottom of the tank that is now getting sucked up when I spray ?