This is the 3rd year that I am using it & it does a great job of cleaning up the black mold here in central NJ. In heavily molded areas, it does not totally remove the mold but it definitely makes it much lighter. You must follow the directions and do 10 sq. ft. at a time. I buy it directly from the manufacturer because it is fresh. I never used another product. It is not cheap but reasonable for the price. I do it in the Spring and Fall, just like they recommend. I have called them a few times and they were very helpful and courteous. I will continue to use the product.