Cast iron is a porous metal, meaning that it will readily take in moisture from the atmosphere, which can tarnish the visual of your fireplace – fortunately though, the solution is a straightforward one.
Whether your fireplace insert has been affected by moisture or general dirt, you can clear it off with WD40 – just squirt it on and rub it off and you’ll be able to remove the tarnishing.
That will leave you with a good starting point to apply a good quality multi-metal polish, which can really bring a shine back to the cast iron.
Before you start, put down some newspaper and wear gloves, as it can prove to be a messy process.
When you begin, only use a bit of the polish as it’ll go a long way, but really use some elbow grease to get into the nooks and crannies.
After leaving it for a bit, get a clean cloth and buff away the polish to leave an impressive shine.