Home Armor® mildew stain remover plus blocker is no ordinary cleaner. It's safe, powerful bleach-free formula eliminates mold and mildew stains, soap scum and mineral deposits like calcium and lime. But, that's only the beginning. As it cleans, it leaves behind an invisible shield that works continuously for up to 3 months to protect surfaces and materials from odor or stains caused by moisture. And its effectiveness is not diminished by washings or rain.