How can i remove stains in the bottom of my cultured marble sinks?

If vinegar doesn't work, try alcohol. Here's a link with more details:

https://www.countertopspecialty.com/how-to-clean-cultured-marble.html

Here is a link for 3 common stains and what to do:

1. Removing Water Deposit Stains
2. Removing Everyday Stains

ref: https://www.howtocleanstuff.net/how-to-remove-stains-from-cultured-marble/

To clean with any of theses, go to an inconspicuous area if at all possible.

Scrub well with a non-abrasive pad.

Get CLR it’s sold T Home Depot. Soak a cloth with the CLR and let it sit over night on the stain then rinse in the morning . If the stain is still there so it again.

You can make use of a capful of bleach together with 32 ounces of water. And just sray it directly on the surface and leave it to penetrate for five minutes. After five minutes, rub with a non-abrasive cloth, rinse with cool water and buff dry.

The one thing that I found that worked was a 1200 grit sandpaper. It is very fine and took the stains off.

Try heated vinegar with blue dawn 50/50.

Vinegar likely etched the marble causing damage which might make it harder now to remove stains. You might reach out to a place that manufactures or sells these types of sinks for further direction.

Hello Ralph, hope this helps you out, a mixture of vinegar and water removes all sorts of stains from cultured marble, including rust and water spots. Rubbing alcohol removes some stubborn stains.

Or

Steps to clean yellowed cultured marble:

1. Mix a very dilute bleach solution (1 capful of bleach added to a 32 oz. / quart spray bottle full of water).
2. Allow the dilute bleach solution to dwell on the surface for 5 minutes.
3. Scrub gently with a non-abrasive pad.
4. Rinse thoroughly with clean water.

Call the suppliers of the Sinks and ask the Technical Department for the answer. Good luck! Might have some luck with WD-40???

This article is asking about a shower, but the tips should still be applicable: https://www.quora.com/How-do-I-clean-deep-rooted-stains-from-cultured-marble-showers

This video might help as well! https://www.youtube.com/watch?v=9gIiFhr_r20

Use a Mild Detergent: Mix a small amount of mild dish soap with warm water and apply it to the stained area. Gently scrub the stain with a soft cloth or sponge. Rinse thoroughly with clean water and dry the area. Marble Poultice: For more stub.