Cleaning Science IV: Ken's Secrets to Cleaning Kitchen Sinks!
Tarnish on Stainless Steel – This is formed through chemistry (oxidation and mineral ions in hard water). The tarnish layer is acidic and requires only A & C to clean. You need a product like Bar Keeper’s Friend™, which has an acidic pH of 1.5 to 2.5. It eats the tarnish instantly, thus temperature and time are not relevant. With the soft part of a sponge or cloth, you can use light agitation to remove the tarnish. For stubbornly tarnished sinks, use more product and more agitation like a scrub pad or light steel wool.
Discoloration on White Ceramic or Stone-Based Sinks – These surfaces are very porous and react with food and the metal in wet silverware. The reaction that occurs discolors the white to a yellow, blue, or orange (rust) color. The most effective solution requires C & T. Use a heavy alkaline like ammonia or bleach with a pH of 11-13. Allow the chemistry to work with a 2-5 minute dwell time (from experience). The stronger the alkaline, the less time is needed.