If they're in a room with a door, try one of those flea foggers you can buy at the supermarket. I bought a bunch of peroxide for 2012. IDK if it goes bad or not. I know bleach does. It was cheaper than alcohol at the time, so I stocked up on it more. When the damnpanic hit, I had a quart of alcohol so Dad was able to use that. Now that alcohol hits the shelves from time to time, I stocked up on it the past couple weeks. I have two gallons of it now in pints. I'm set.