Wet And Forget 6318344 Moss Mold Mildew and Algae Stain Remover, 1 Gallon, 2pk Can be used for moss, mold, mildew and stain removal on any exterior surface. Safe for any outdoor surface Safe for use around plants Non-Caustic, Non-Acidic, and No Bleach No Scrubbing, Rinsing, or Pressure Washing.