If you mean the dark ring or black/brown stain around a faucet base, it is usually caused by hard-water minerals, soap residue, mold/mildew, or grime buildup. Try these methods:
1. Vinegar method (for white crusty mineral deposits)
- Soak a cloth or paper towel in white vinegar.
- Wrap it around the stained area.
- Leave it for 15–30 minutes.
- Scrub gently with an old toothbrush or soft sponge.
- Rinse and dry completely.
(Avoid leaving vinegar too long on natural stone surfaces like marble or granite, as it can damage them.)
2. Baking soda paste (for stubborn stains)
- Mix baking soda with a little water to make a paste.
- Apply around the faucet base.
- Leave for 5–10 minutes.
- Scrub gently and rinse.
3. For black mold-like marks
- Use a bathroom cleaner designed for mold, or a diluted bleach solution if the surface allows it.
- Never mix bleach with vinegar or other cleaners.
4. Prevent it from coming back
- Wipe around the faucet after use.
- Dry standing water near the base.
- Clean weekly with a mild cleaner.
If you can share a photo or tell me whether the dark circle is black, brown, green, or white/chalky, and whether your sink is ceramic, stainless steel, marble, or granite, I can suggest the safest method.
