According to the CDC, you need to use either 75% alcohol or 75% Clorox to 25% water. I got a spray bottle and I mix it up fresh every week. I hope that alcohol starts appearing in drug stores sometime soon - I am running out. I wear the mask whenever I go out. It seems like it is so easy to get. That NBC doctor got it because he wasn't wearing goggles - I didn't even know goggles were necessary! I'm so grateful for the scientists and doctors that are speaking out.