This stain remover lets you spray and leave on, with a no-rinse application. It is bleach-free and safe for use on virtually any outdoor surface. Moss, mold, mildew, or algae stains are cleaned over time without any scrubbing. Originally listed at $29.99, is now marked down to just $19.99. Shipping is free for Prime members or non-members get free shipping for over $25+.