Calcium deposits on stainless steel sinks will mar the sink's appearance and create stain-like marks on the metal surface. These deposits are caused by dissolved minerals in the water that harden as the water evaporates. The longer you leave calcium deposits on stainless steel sinks, the harder it is to remove them.
Rinse the stainless steel sink with water. Scrub the sink with a sponge to remove surface grit, debris and any loose mineral deposits.
Pour straight, white vinegar into a glass or ceramic bowl. Place the bowl in a microwave and heat until the vinegar is warm. Pour the vinegar into a plastic spray bottle. Spray the vinegar onto any calcium deposits or mineral deposits. Coat the stainless steel sink generously and soak the deposits thoroughly. Allow the sink to soak for 5 to 10 minutes, or longer on severe mineral deposits. The natural acids in the vinegar will eat away at the mineral deposits and help to remove the calcium.
Scrub the sink a second time without rinsing away the vinegar. Focus the scrubbing on the mineral deposits you wish to remove. Rinse and spray again if there are trace elements of minerals left behind.