Same thing works with windshield washer bottle on your cars when they get plugged up.
Got it to some Peterbuilts that the guys would use straite water in instead of washer fluid. They would get plugged up with hard water, then they would not work.
Throw some vinegar in there and watch it start foaming up, next thing you know the sprayers are spraying again. Good stuff, thanks for the rust tip. Kurt