If you notice rusty spots on your kitchen knives you will probably not want to use them. Before tossing them, soak the rusty parts in a bowl of white vinegar for about 10 minutes. Remove and gently scrub with a sponge, rinse well, and dry. The acetic acid in the vinegar reacts with the iron oxide (the rust) to dissolve the rust so it will wipe away. Drying quickly prevents new rust from forming. Rub a paper towel with a drop of cooking oil on it carefully over the blade to create a barrier that will keep moisture from reaching the metal and causing rust again.