Put on your rubber gloves, gather the cast-iron pieces you wish to clean and find a well-ventilated area in which to work. Oven cleaner fumes can become overwhelming if you’re not careful.
Coat the cast iron in oven cleaner, spraying it thoroughly. Try not to get it on your skin or breathe in the fumes.
Place the cast iron into a plastic trash bag and tightly tie the bag shut. If you wish, you can use a plastic tie or rubber band to seal the bag. The plastic should be airtight to prolong the cleaning action.
Lift the plastic bag carefully, so as not to rip it, and set it in a safe place. Allow the cast iron to soak in the oven cleaner for about two days.
Remove the cast iron while wearing your protective gloves, and move to the sink.
Scrub the cast iron under water using a scouring pad. Mix in a small amount of dish detergent, just enough to create suds. If the cast iron is still rusty or extremely dirty, use a wire brush to scrub. Continue until you’re satisfied with the results.
Dry the cast iron immediately with towels. Do not allow the cast iron to soak or remain wet, as it will cause rusting.
Use a clean towel to apply a light coat of vegetable oil on the cast iron, especially if you will be storing it. This will help prevent rust.