Soak the sink with a bleach solution. In an empty plastic spray bottle, combine a 1:1 solution of bleach and water. Lightly shake the bottle to mix the solution. Open the window or turn on your bathroom fan before you start spraying the bleach solution, as this will provide ventilation. Then, spray the bleach solution over the entire interior surface of the ceramic sink. Let the bleach mixture sit and soak for about 10 minutes. Then, use a sponge or an old rag to wipe the sink clean.
Bleach is a strong chemical and can be very harmful if ingested or sprayed in the eyes. Use caution when spraying bleach, consider wearing safety goggles or at least rubber gloves, and wear clothing that you don’t care about. If there are young children in your house, make sure that they’re not near the sink when you’re spraying bleach.
Apply cream of tartar and vinegar. If you would prefer to not use any chemical cleaners, you can remove stains from the ceramic with a mixture of cream of tartar and vinegar. Combine the cream of tartar and the vinegar at a 1:1 ratio in a small mixing bowl, and stir them together. Then, spoon some of the mixture onto the stains on your ceramic. Let this sit for about 10 minutes, and wipe clean with a sponge.
This method will also work if you substitute hydrogen peroxide for the vinegar. All three of these ingredients can be purchased at your local grocery store or supermarket. Scrub the stain gently with a pumice stone. Pumice stone is quite abrasive and can scrub stains off of your ceramic. Before using, run the pumice under water, and make sure that the stone stays wet while you’re rubbing out a stain. Then, lightly scrub at the stained area of your ceramic sink. The pumice should remove the discoloration.
Be careful when using this method. If you apply a pumice stone to a ceramic sink, the stone may scratch or damage the surface. Begin by rubbing gently, and stop if you see any scratches forming.