You can open it up and take out the reactor if there is not time to allow it to cool down. Cooling down will help prevent CLO2 outgassing, but if you are quick taking out the reactor, you won't have a problem. Be careful not to let any reactor solution spill into the CDS. I throw the spent reactor solution outside and not down the kitchen drain because of our septic tank. After taking out the reactor, then put the CDS in the fridge until you need to use it. Or, you can wait until you get home from work to take out the reactor. Not much more activation will happen in the reactor beyond 12 hours, maybe less, depending on temperature.