How to Clean Rust Marks From Metal Surfaces
To remove rust spots from tools and equipment, soak the affected area in lemon juice for a few minutes and then wash it.
Lemon juice also removes black oxidation marks from silverware. Non-stainless steel items, like non-stainless carbon steel knives, though may get a patina when treated with lemon juice or lime juice.
You can buff out the stains by scrubbing them with an aluminium or tin foil. For tough stains, apply a mixture of one part of hydrogen peroxide and three parts of cream of tartar on the affected area. Allow it to dry for some time before wiping it off with a damp cloth.
You can soak equipment like garden tools in white vinegar overnight and clean them the next day. Similarly, for rusted screws, nuts, bolts, etc., consider spraying vinegar on them or wrapping them in a rag soaked in vinegar.
Some other remedies for removing rust, particularly from stainless steel items include club soda, a mixture of one tablespoon cream of tartar and a few drops of lemon juice, and a combination of lemon juice and baking soda.