How can I wash the stink out of my pack?

After pulling my large backpack out of storage in my attic, I was dismayed to find that it stinks to high heaven. Are there some big guns that I can pull out to deodorize it without daging the pack?

Anyone make a dual bladder hydration pack?

I'm looking for a hydration pack with two bladders and a toggle switch to let me move back and forth from one to the other while cycling. Is there such a thing?