Tape off the edges of the wall surrounding the fireplace with painter's tape. This will help protect the wall from any paint splatter. Tape off any metal on the fireplace surround, as this will be painted in another step.
Open the can of oil-based primer and mix carefully with a stir stick. Dip a chip paintbrush into the primer. Carefully dab on the brick, using a blotting motion. Dabbing in small strokes helps the bricks absorb the primer and helps fill in all the grooves and textures in the brick's surface. Allow the primer to dry completely.
Apply one coat of an oil-based paint over the oil-based primer, covering all of the brick. Used the same blotting method described in the previous step. Work from the top down, so you can fix any paint drips as you paint. Allow the paint to dry. Apply an additional coat if necessary.
Remove the painter's tape on the metal surround. If the fireplace has a glass front, cover this surface with painter's tape. Cover the painted brick immediately around the metal fireplace surround with a painter's drop cloth. Use painter's tape to hold it in place. Also, cover the floor with a drop cloth.
Use a heat-safe spray paint to transform the metal from a shiny brass to a contemporary color better suited to the home's decor. Spray in long, even strokes to encourage even coverage. Allow the spray paint to dry and apply another coat if necessary.