At the very least you need a nasal spray bottle. Optimally you should use a nebulizer. CS will only kill what it comes in contact with. Flu virus likes the warm, dark wet lung area for festering. You need to get CS into the lungs to improve your chances of success. As soon as symptoms are noticed, I would take CS orally and also nebulize every hour into the lungs.
MMS in addition would be synergistic if combatting the flu.