Our shower is awful and needs replacing. In the meantime we have resealed round the tray with a combination of that strip stuff you can buy plus dh then sealed around that with sealant (is it silicone?) The problem is it's all gone black and mouldy. We've got visitors this weekend and I am really embarrassed for them to see the state of the shower cubicle! I got some of that Mould and Mildew remover and left it on for a good half hour before rinsing off - have done this twice now - it has had no effect whatsoever. What can I do to get rid of it? Or are we going to have to peel all the sealant off and start again? (Can't scrub the sealant too hard or it starts coming off!)