Gel will totally evaporate. Reapply as necessary. The clinging gel allows product to be applied on horizontal, vertical and irregularly shaped surfaces. Its slow releasing formula continuously provides fragrance for extended periods of time. Ideal for use on hard, non-porous surfaces. Spray on air conditioner filters, above doors, in trash receptacles and dumpsters, on walls, in port-a-toilets, above ceiling fans and behind toilets. Areas of use include in automobiles, homes, laundry rooms, pet areas, hotels, schools, municipalities, hospitals, kitchens, nursing homes, anywhere!