How do I restore my yellowed faux marble?

Plastic yellows over time, not much you can do. Sorry.

Hi Carolyn,

You could try making a paste of baking soda and hydrogen peroxide. That MIGHT help, but as Kelli stated, plastic does turn yellow over time. If it's a faux marble, you might be able to paint it, Here's a blog post from someone who did just that. Wishing you the best.

The process.

https://www.domesticimperfection.com/how-to-refinish-outdated-tile/

One year later.

https://www.domesticimperfection.com/my-painted-shower-one-year-later/

You can now purchase kits that will color almost anything. See if you can buy one to redo your marble.

You can try to "restore" the finish by using a kit, like this one: https://www.amazon.com/gp/product/B000PTSBKW/ref=as_li_ss_il?ie=UTF8&linkCode=li3&tag=domestiphob05-20&linkId=371fef3b62f73a8aa4ddeea0b88054ae

Or invest in a new one. I'm surprised that at 25 years old the stall hasn't started showing signs of cracking in addition to the white turning yellow!

Thanks for the suggestions

Hi Carolyn, create a dense paste of more baking soda and a little bit of water. Apply the paste to the stain and leave for a few minutes before wiping it off. You may need to repeat until the stain vanishes. If it’s a tough stain try removing it with ammonia solution. Dilute the ammonia with water 1 part ammonia to 10 parts water. Test in a small spot first. Rinse the solution from your marble well to eliminate any residue, left from the cleaning ingredients on it and wear gloves.