The rag trick. This method, the easiest and quickest, involves wiping the stain with a cloth soaked in vinegar. Vinegar is a natural disinfectant that removes yellow or black stains while also thoroughly polishing and disinfecting. If the stain persists, apply vinegar directly to the stain and wipe it off with a cloth after about 30 minutes.
Lemon. This citrus fruit also has antiseptic and lightening properties that can help remove stains. Rub half a lemon directly onto the dark stain, let it sit for a few minutes, then wipe it off with a cloth. Repeat this if the stain doesn’t disappear.
Borax. This is one of the most powerful stain removers for virtually any bathroom surface. Apply borax directly to the stain, then pour vinegar over it. After 20 minutes, scrub with a sponge, rinse with water, and dry thoroughly. Wear gloves and a face mask when applying borax.
