Step 1
Saturate a sponge in pure white vinegar. Scrub the brown stains carefully with the saturated sponge. Rinse the sink with cool water and wipe dry with a lint-free towel. Continue if the stains remain.
Step 2
Add 1 tbsp. of 3 percent hydrogen peroxide to 3 tbsp. of cream of tartar. Stir the peroxide and tartar together to form a thick paste.
Step 3
Apply a dollop of the thick paste to a clean, damp sponge. Scrub the brown stains with the paste in the direction of the grain.
Step 4
Rinse the paste off the stainless steel sink with cool water. Dry with a towel.