I've been using the original Krud Kutter for years. It's always been an excellent choice for cleaning aircraft hangar floors and general degreasing. (I love that it's nontoxic and biodegradable!) This is my first time using this particular product and it does not disappoint! Our tile shower had developed some stubborn black mildew on several grout lines. Following the directions, I sprayed the affected area, waited 5 minutes, and found that it came off INSTANTLY with a scrub brush and minimal effort. This cleaner is another win for Rustoleum's Krud Kutter line of products! Well done!