There are a lot of lakes around here that don't allow live minnows for fear of introducing unwanted invasives. Taking a dozen or two and putting 'em in a baggie with a fist full of kosher salt preserves them, and makes them legal to use as bait.
Just remember that they'll absorb water, and change bouyancy. I use an adjustable Venom float for a neutral presentation, and I'll have to adjust the length of foam to compensate.