I do not use harsh chemicals in my home. This is a harsh chemical definitely use in a ventilated room. Opening windows is a must! My daughter dyed her hair red and the dye was very strong it left the shower looking like a massacre. I tried all my natural cleaners and the stain laughed at me. With gloves on I sprayed this on very well with the window open then made sure to close the door while it soaked. A mask is a must. This is a very strong chemical spray. I checked and repeated maybe 3 more times till it was completely gone then rinsed. I never scrubbed!! This stuff took care of everything. My shower looked way better then before the massacre. Only harsh chemical I will carry from now on. Do not let children use this stuff it’s hard-core.