Spray a microfiber cloth with furniture-dusting spray. Wipe the tabletop to remove surface dirt and dust.
Pour ketchup directly onto stained or tarnished areas of the copper tabletop. Gently buff the surface with paper towels. Dampen a paper towel with water and wipe off ketchup residue. Dry the copper with another towel.
Apply a quarter-sized amount of furniture-polish wax to a soft, clean cloth. Rub the wax into the copper tabletop to protect it from moisture and stains. Buff the table with a dry cloth to remove excess furniture wax from the copper top.