Contact the cemetery administration or the National Cemetery Preservation Commission in your area and ask for permission to clean, paint and restore the headstone.
Choose an oil-based enamel granite paint that matches the current stone colors. Most headstones are made with black and white granite, but others have a brownish color. Be sure to use a granite finish stone paint. This type of paint is made to protect porous materials from inclement weather.
Spread sheets of plastic around the headstone so paint and debris will not spatter on the grass or concrete base.
Spray water on the surface and use a sponge or damp cloth to remove dirt and debris from the headstone. Add a few drops of dishwashing soap to a bucket full of warm water. Wipe the headstone with the cloth, wring it out and dip in the soapy water again. Continue wiping until the dirt has been removed. Fill the bucket with clean hot water and rinse off the soapy water. Scrub dried flaking paint with a stiff bristled nylon brush. Avoid using wire brushes as these cause scratches that allow for lichens, a type of fungus that can grow on stone.
Apply masking tape over the lettering to protect it from being painted the granite color.
Shake and mix the granite paint thoroughly. Stir it with a paint stick and be sure to stir the sides and bottom so you get an even color throughout. Add sparkle crystals, which you can purchase separately, if you want a sparkly finish. Follow the package directions for mixing the crystals in the paint.
Dip a medium-size brush in the paint, wetting the tip only, and paint in smooth vertical strokes from the bottom to the top. Allow the paint to dry overnight. Apply a second coat if needed and allow to dry. Remove the masking tape from the lettering. Apply tape to the outer edges of the lettering to keep from spattering or painting the fresh granite paint.
Shake and stir gold, bronze or the same color paint as the current lettering. Dip a ½-inch brush tip in the paint and slowly retrace the lettering on the tombstone.