When I play multiple saxes I generally use fibracells on the horns that I'm not playing as much during a concert or rehearsal. I've seen people advocating soaking reeds in a glass of water before hand and I've seen people employ the use of a sponge attached to the inside of a mouthpiece cap. The Oboe and Bassoon players that I know tend to have a small medicine cup or shot glass filled with water and have their reeds in it. I'd love to hear from some folks playing in pit orchestras for their experience and solutions.