Simply spray it on with a standard sprayer on an y hard surfaces and watch; the mold stains are gone within 15 seconds. Simple and Quick! It's our powerful bleach-based patent pending formula. No more time-consuming sanding and scrub brushing. We recommend using last RMR Botanical cleaner to treat all surface after RMR-86® jabs been applied. It's an excellent odor neutralizer treatment and masking agent to remove any leftover odor from RMR-86®. Has superior penetration into porous surfaces such as wood, concrete, drywall, tile and grout, fiberglass, vinyl and more. Works great all around your home. It's amazing on boats too.