HouseTask.com describes rust as "a type of corrosion that attacks ferrous metals such as steel and iron when they are exposed to a mix of water, oxygen and carbon dioxide." Rust can attack even the cleanest of refrigerators. Once rust appears, it can spread quickly. Removing rust as soon as possible is very important, as long-term rust exposure can mar the appearance of and weaken your refrigerator, forcing you to buy a replacement.
Removing Rust on a Refrigerator
Clean the affected surface of the fridge by wiping it down with a damp cloth and some dish soap. Wipe firmly to make sure there are no food particles left on the surface and to get rid of any excess dirt and grime.
Mix 1/2 tsp. of salt with 1 tbsp. of lemon juice. This will form a watery paste. Rub the paste on the rusted area. Allow the mixture to sit on the rust for a few hours, then clean it off with a damp cloth.
Mix vinegar with water in a small cup or other receptacle. You can make this mixture stronger by adding more vinegar than water, or weaker by adding more water. Apply the mixture to the rusted areas of the fridge and scrub with the rough side of a dish sponge. Allow the mixture to rest for an hour, then wipe it off with a damp cloth.
Use a rust remover from a manufacturer. If natural products have not gotten rid of the rust, try buying a rust-dissolving product. These are available at hardware or home improvement stores. Simply apply the product to the rusted area, and let it sit. When the rust is gone, wipe down your fridge with a damp cloth.
Sand the rust-free area, wipe off with a cloth, and using the paint brush, apply a coat of anti-rust primer purchased from a hardware store. Apply a coat of matching (if possible) paint. This will help to prevent the rust from reappearing.