Comet Mildew Stain Remover GelMildew Stain Remover Spray Gel This innovative spray gel cleans mildew stains like no other spray.The gel formula sticks to the mildew stains so it can better bleach away disgusting mildew stains with less work. Comet Spray Gel Mildew Stain Remover is easy and convenient to use and leaves no messes because the gel formula doesn"t run away from stains like traditional liquid sprays do.