You can mask off anything beforehand with builders' paper, plastic bags, tape, layers of newspaper, etc. I'd try strong soap and water first on a test area. Use three kinds of brushes: stiff short bristles, medium stiff long bristles and a couple of old toothbrushes. However if that doesn't work, head to a fireplace shop and buy a hearth-cleaning product there. There are some fierce ones, based on lye. Use gloves and ventilation (if spraying it on, use a mask and goggles). Test in a hidden spot first to make sure it doesn't harm your mortar. Be patient, it's a pain to do. Don't saturate up too-large an area at once, even if it says to let it "work" for a bit. It will be time consuming and you don't want the stuff to dry out while you're working on another area. Have lots of paper towels on hand, and a bucket (not paper or plastic bag) to put the used ones in. They can easily mar other surfaces if they are wet after use. HTH L.

To answer questions, yes we gutted and opened up this home. We want our family room just inside the front door as it functions well for watching children playing outside. (Rather than a formal living room, but we want to create a NICE space) The dining room has the fireplace and is open to the kitchen, which has an amazing 10’ island with a bar height side with 4 seats and then a counter height end for food prep. We’re loving the kitchen tho still waiting on light fixtures and backsplash. The flow is working well for us but the furniture placement and how to highlight the fireplace and it’s area is the challenge! Thank you BTW we DO have another room that would serve as the formal dining room but we don’t have that need at this time and are using it as a lovely home/mom office and playroom, so toys stay in there and not all over the house.

Are you currently living here, just moving in or putting it on the market? As for your specific questions; look into getting a new mantel, much thicker and interesting, that can be slipped right over the current one. If you find the brick too dark, consider doing a whitewash or a German Smear technique on it. Heat proof black paint can freshen up the metal parts of the heatilator. What material is the wainscot? Is that just paint below or some kind of wood or product? Paint might be the key to that issue. A round table would work well in the squarish room. I'd look for more of a farmhouse style chandelier. If you're just moving in, I would wait on anything major in the kitchen. For now, just remove the wallpaper and paint it. Light sage green will look good with the pine cabinets. I can't tell much about the rad, but a table built in right over it might work if the height is correct. Look for radiator cover under Photos here at Houzz for ideas. You might replace it with a lower style one and then build a bench over it. Rad bench German Smear on brick

I would recommend using a magic eraser to clean up what you can, then get some heat resistant black paint and paint over the entire black area.