Sweep the entire surface of your cast iron fireplace vigorously with a wire brush to get rid of any remaining debris. Dampen a cotton cloth with a few drops of mineral spirits, and wipe down the fireplace’s surfaces with it. This will remove fine dust.Click to see full answer. Similarly one may ask, how do you restore a cast iron fireplace?Wipe Down With White Spirit: Clean off the fireplace with a cloth soaked in white spirit once you’ve got the paint off. Don’t let water get anywhere near the cast iron or it will start to rust quickly. Remove any Rust: If there is any rust on the fireplace, use wire wool to clean it off.Subsequently, question is, how can I make my iron shine? Steps Make up a mixture of 1 tablespoon of baking soda with 1 liter (0.3 US gal) of water. Sponge the wrought-iron furniture with this mixture. Allow to dry. Wipe down with a soft cloth. The wrought-iron should look a lot better. Then, how do you clean a matte black cast iron fireplace? To initially clean your matt black cast iron fireplace, you should provide it with a light polish using a soft brush or a show brush. Never use a damp cloth to clean fireplaces of this style as otherwise you risk facing the occurrence of rust.Can you use wd40 on cast iron?WD40 will not hurt cast iron, but will not do much to help it, either. WD40 is mostly kerosene or a very similar aromatic hydrocarbon. WD stands for “water displacing.” That is what WD40 was designed for, not for lubrication, not for corrosion protection.