Ugly grout stains and old white mosaic like bathroom floor tiles

https://www.hometalk.com/categories/cleaning/household/grout

Commercial grade bleach and a scrub brush on the end of a paint extension pole. It's going to take elbow grease, but once you've gotten it clean, reseal the grout with a grout sealer. Good luck.

Clean it up good and rub white enamel paint into the grout lines.

You can look at products like Grout Refresh: https://www.amazon.com/Grout-Refresh-8oz-Bottle-white/dp/B006IS9B2G

Use a solution of white vinegar and baking soda , a brush and lots of elbow grease.

Cleaning Grout with Hydrogen Peroxide, Baking Soda, and Dish Soap

1. Make a paste.
2. Apply the paste with a nylon bristled brush.
3. Let the mixture sit on the grout for 15 minutes.
4. Rinse the grout with warm or hot water to remove all of the solution.
5. Use a rag to wipe the grout to remove any leftover residue or dirt.

Mop the floor with clean water.

OR

Making a paste with OxyClean ans scrubbing works well too.

Once it's clean, SEAL!

Use hot water + Oxyclean, let it set, then scrub clean. After drying put White Enamel

paint on old grout. Wha la...New bath !!!

I use Oxyclean on most all my cleaning, however I just discovered that even the store brands of "The Magic Eraser" works GREAT ! Cleans not only the soapy - mildewy scum but even the Rust that may accumulate and I agree that once you get it white again, seal it with a grout sealer.

Make a paste of baking soda and peroxide then apply it to your grout with a toothbrush. Let it sit a little and then remove with a clean cloth.

Hi Jackie, hope this helps.

Mix up a solution of about 3 tablespoons powdered oxygen bleach (something like OxiClean would work) and warm water in a 2-gallon bucket. With a sponge or cloth, swipe it around the surface until the grout lines are full. Let it soak in for at least 15 minutes, then rinse well with clean water. Once you get it clean, you can seal it to prevent it getting ugly again.

https://www.youtube.com/watch?v=YkmErGLH1DY

I would try peroxide and baking soda. Peroxide will whiten and the baking soda is a mild abrasive.