Salt and citrus method
Cover the affected area in salt. Squeeze the juice of one lemon over the salt. Leave for a few minutes. Using the lemon rind, rub off the residue.
Potato and dish soap
Cut a potato in half, covering the fresh surface with dishwashing liquid. Rub the soapy potato on the item and watch the surface rust disappear before your eyes.
If possible, submerge the item in vinegar. Soak overnight, scrub and rinse. Remember, vinegar reacts differently with certain metals. Steel tools should be fine to submerge, however, vinegar may cause stainless steel and enameled cast iron cookware to corrode.