the mold is sprayed, waited 1 hour and then washed off, just as it is described on the package. the chlorine-containing bleach products in addition, but this one has this acrid smell of chlorine. Often here the bleach is equated with killing the mold spores, but this is wrong-both have nothing in common. As here in chlorine-free mold remover to the "dead" molds must wipe even with chlorine-containing products after the contact time, only he's here just still visible until you then wiped him. For residential or even dormitories I would always recommend and use the chlorine-free mold remover!