In September '23, the scaffolding that had been erected for the installation of external thermal insulation was taken down, and one of the legs was rusty, leaving a mark on the tile. In May '24, I used this specific cleaner, and the rust was removed on the first attempt. Then, I cleaned years' worth of dirty joints with just one spray. Finally, I used it on tiles with rust and dirt, placed in a half-finished building over 7 years old. Here, the process had to be repeated 3 to 4 times, and I estimate that 90 to 95% of the rust and dirt was removed. So far, due to work, I haven't repeated the process on those specific tiles. Today, I had the brilliant idea to use it in the toilet to remove grime that wouldn't budge with chemicals, steam cleaners, baking soda, vinegar, and other concoctions. I removed the water from the toilet, sprayed, waited 10 minutes, scrubbed with a sponge, and finally! I highly recommend it.