Soak paper towels with full-strength white vinegar and lay them over the mold spots on the stainless steel. Leave the paper towels in place for 10 minutes to kill the mold spores.
Remove the paper towels and discard. Wipe the surface of the stainless steel with dry paper towels.
Pour 2 tablespoons of white vinegar into a bowl and add 1 tablespoon of table salt. Stir the mixture to create a paste.
Dip an old toothbrush in the paste and scrub the mold stains remaining on the stainless steel surface. Rinse the brush frequently. Apply more paste and continue to scrub.
Wipe the stainless steel surface with a clean cloth to remove the paste. Moisten another cloth with white vinegar and clean the stainless steel surface. Dry with another cloth.