Pour 4 ounces of both white vinegar and warm water into a bowl. Stir the diluted vinegar solution.
Dip a nylon scouring pad in the vinegar solution. Gently scrub the white hard water marks with the pad.
Continue scrubbing the enamel sink with the solution until the chalky marks dissolve. Prepare additional vinegar solution, if necessary.
Moisten a cloth with fresh water. Wipe the enamel sink to rinse off the vinegar.
Buff the enamel sink with a soft towel. Thoroughly dry the sink’s surface.
Moisten a cloth with water and a drop of dish soap. Squeeze the cloth to form soapsuds.
Wipe the enamel sink with the soapy cloth. Remove as many food marks as possible.
Inspect the enamel sink for lingering food residue. If grimy food marks persist, dampen another cloth with water. Coat the cloth with baking soda.
Scrub off the remaining food marks with the damp baking soda. Rinse the cloth frequently and re-coat it with more baking soda, if necessary.
Moisten another cloth with water. Wipe the enamel sink to rinse off the baking soda.
Buff the enamel sink with a soft towel. Thoroughly dry the sink’s surface.