If you buy a ready-made mantel, do not be afraid to paint it or add moldings. A easy hearth makeover can start with gadgets you have already got in your home. Shop your existing inventory of equipment and show a quantity of in your mantel for a fast, no-cost refresh. Stainless metal, stamped tin, wrought-iron grillwork, glass, and wooden painted to match your flooring or counter tops are all possibilities. “The process is straightforward,” says Mike McAllister, proprietor of Riverside Kitchen Center in Mount Vernon, Washington. “Remove the small flange that holds the prevailing insert, then replace the insert with …