The presence of mold in areas like tile grout, shower caulking, washing machine and fridge gaskets — and even on surfaces you can smell but can’t see — is pretty concerning. It’s often an even bigger challenge to effectively remove and prevent it from coming back. Fortunately, reviewers insist that this mold and stain fighter will actually do the job, even going so far as saying it removes years-old mold from washers, showers, toilets and more. As one reviewer puts it: “This finally works where everything else fails.”

Made by Active, which makes a super-popular easy toilet bowl cleaner, this formula is highly concentrated and sticks to even vertical surfaces thanks to its gel consistency.

According to its many supporters, the cleaner tackles stains and black mold on tile grout, caulking, and even areas like gasket seals in their washing machines. It’s so effective that several reviewers have claimed that it’s prevented them from needing to replace things like shower stalls and grout, since this restored surfaces to “like new” conditions, while also preventing the mold from coming back.

“Had these stubborn mildew stains in the calking of our shower that no matter how much bleaching and scrubbing I did, it would not come out,” explains one reviewer. “Saw this still and had to try it. Worked like a charm.”