Small Cast-Iron Objects
Pour 2 L. of Coke into a bucket, tub or sink.
Let the cast-iron object soak in the Coke for 24 hours.
Rinse the Coke off the cast iron with clean water. Dry the object with a clean cloth.
Apply a light coat of wax or vegetable oil with a clean, dry cloth to protect the cast iron from future rust.
Large Cast-Iron Objects
Set your cast-iron object on top of a tarp. It is best to clean your large cast-iron object in a garage or outside, as the cleaning process can get messy.
Pour Coke over the rusty spots of the cast-iron object. Let the Coke sit on the rust for 15 minutes.
Saturate a sponge with Coke and scrub the rusty spots.
If the rust remains, pour more Coke on the cast iron. Wait 15 minutes and scrub again. Repeat this process as often as needed until all of the rust is removed.
Rinse the cast iron with clean water. Dry the object with a clean cloth.
Coat the cast iron with wax or oil to prevent future rust.