Usually a product with bleach works best , I use either comet with bleach or and make a paste with water ( or soft scrub with bleach ), spread it on the grout , let it sit for about 20 minutes, then scrub with a grout brush ( like an over sized toothbrush with stiff bristles ) then rinse . If necessary repeat . Unfortunately , sometimes it is too late and the mildew has embedded itself into the grout , at that point , the grout will need to be scrapped out and replaced . Make sure to open the window when using bleach and don't use other cleaners while using bleach , the mix of fumes can be dangerous !!! Once you have cleaned the mold/ mildew prevention is important, at least to make your life easier !!! Mold likes damp conditions !!! Always use the bathroom vent or crack the window. Also leave the bathroom door open , after your shower , to let the steam and dampness out and the room to dry out . You can keep a squeegee in or next to the shower and use it on the tiles/ shower door before getting out of the shower, this helps big time !!! By getting the water off the grout right away.
We use a Hurricane Turbo Scrubber. We ordered ours online, but you can get them at Walmart now and maybe other retail stores. They take all the hard work out. We use our regular cleaning soap, Simple Green , and it works just fine! They are about $40, but they do so much more on the oven, range top, even tires of the car! We love ours!
Wet and forget shower is a great no scrub product. I would recommend twice a week until clean then once a week for maintenance.
I'll tell you what I did..... It worked VERY VERY Well.... but is not recommended on the label of the product......
I had severe stains in the shower that would not come off after 20 years of a families abuse and I was so sick of it not coming clean that I took a bottle of "The Works" and squirted it all over the shower walls and floor...... It smelled awful and I had to open the window and turn the bathroom vent fan on.....
I let it sit a few minutes and went back in with a steel wool pad and all the years of "yuck" came right off.....
That is the whitest that shower has been since it was new....
Had one bad spot on the floor that I did a second application to and it came clean.
I was proud.
If you try this, I do recommend lots of ventilation and a bandana over your face, because it is rough smelling..... and rubber gloves!!!!
Hi Dt. I'm Cindy. I recommend using a product called Oxi Clean Max Force. Use an old toothbrush to scrub it in to the grout and let it set 15 or 20 minutes. Then come back and wipe it all up with a clean cloth. Repeat if necessary.