: For stubborn black patches, mix white vinegar and baking soda into a thick paste. Apply it to the vessel, wait for 10 minutes , then scrub and rinse.
: This is a classic Indian method for old brass. Soak a small ball of tamarind in warm water to make a thick pulp. Apply the pulp all over the kadhai and let it sit for 10–15 minutes . Scrub gently with a soft sponge; the natural tartaric acid will "melt" away the blackness. : For stubborn black patches, mix white vinegar
: For very thick layers of grime or grease, boil the kadhai in a large pot with water, 2 tablespoons of salt, and 2 tablespoons of vinegar for about 15 minutes to loosen the buildup before scrubbing. How to Clean Brass Utensils at Home Soak a small ball of tamarind in warm