I bought the miracle mould remover gel to get black mould out of the shower seal so I didn’t have to re-silicon. I applied as per the instructions and left it on for 5 hours. When I removed it the mould was significantly reduced. With a second application I expect it will be barely noticeable, and there’s definitely enough left in the tube to do that. My only gripe was that the nozzle end didn’t have a hole in it and I couldn’t make one so I used a large syringe to apply it. There was no odour during the application, and a light odour (windows open and fans on) during the soak and during removal. The gel washed away down the drain pretty easily. I used rubber gloves to apply and remove. I’m happy with how it turned out.