Best product on local hardware store for fireplace rust removal?

Hello! winter is coming fast. Our gas fireplace has rusted parts on the casing. The whole casing is not considered as a replacement part unless I want to buy a new fireplace I also don’t want to dismantle this big chunk just to scrub it. What is the best product available on local hardware stores that you used (spray) on removing rust on iron or metal fireplaces with little scrubbing?

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