Got mould or mildew stains in your toilet? Not a problem. Oh no. Not a problem at all. Here's a good trick: all it takes is a little bit of Duck® Foaming Bleach Gel. And a solid pour. Basically, you just pour on some Foaming Bleach Gel to treat those stains. That's about it. Really. There's nothing more to it. Foaming Bleach Gel helps lighten and whiten stains around the toilet bowl. I don't mean to get too scientific, but it's the bleach that makes all the difference.